If there's one lesson out there that applies to all relationships, it is that the truth will come out eventually.

And if you need more proof of this, then check out the story of 24-year-old TikTok user Sydney Kinsch, who recently took to the social media platform to reveal how she discovered her ex-boyfriend was cheating on her.

After being sent a seemingly-innocent Snapchat by her then-boyfriend, Sydney noticed a tell-tale reflection in his sunglasses.

Sydney captioned her post: "check the reflection in your boyfriend’s sunnies ladies. [sic]"

Take a look at the TikTok video in question below: 

[[tiktokwidget||https://www.tiktok.com/@sydneykinsch/video/6890397554001988869]]

She also wrote over the video: "That one time my boyfriend of 4 years snapchatted me him cheating on me [sic]".

Upon a closer inspection of the image, Sydney saw something very shocking indeed. That's because there, reflected in the lens of his shades on the passenger seat, was another woman wearing shorts and stretching her feet out of the car's window.

Needless to say, a number of people enjoyed the video, and in just six days, the post has been viewed over 2.2 million times.

And many Tiktokers took to the comments section of Syndey's post to slate her cheating man:

[[imagecaption|| Credit: TikTok]]

For instance, one TikTok user wrote: "Everything always comes out one way or the other." Meanwhile, another sympathetic person added: "What's done in the dark comes out in the reflection of your sunglasses!"

[[imagecaption|| Credit: TikTok]]

[[imagecaption|| Credit: TikTok]]

And it seems like this is a rather common way to catch cheating partners, as one commenter wrote: "How I caught my ex too. Reflection in a window."

And another TikTok user chimed in: "This legit happened to me!!! My ex took a selfie to send me and I saw a chic in his glasses reflection lol [sic]"

[[imagecaption|| Credit: TikTok]]

[[imagecaption|| Credit: TikTok]]

Another quipped: "Don't know why he's got the sunnies on, he's not that bright."

So the next time your partner sends you an innocent-looking selfie, you may want to check out the surrounding reflections.

When an entire lifetime is chronicled in its fidelity online, the digital record becomes itself a public record of memory. No matter what happens to you, a good portion of it, particularly relationships, will be preserved online for all of eternity, whether you wish for it to exist or not. Short of deleting your Instagram, there is no way to absolve this public memory of a past relationship. It remains, eternal. At least, unless you edit it. If you return to your timeline with a fine-toothed comb and serve away all the bad memories, you can excavate a relationship and replace its bones with something else entirely. You can force in foresight, and create an alternative past where the bliss of ignorance never existed, and all along you knew that a particular person or time in your life was a disaster. You can literally rewrite your own public memories, until the present looking back at the past replaces the past entirely. What, then, becomes of authentic human experience? This woman, whose name has been blurred to protect her anonymity, did exactly that. Returning to her Instagram in the wreckage of a bad relationship, she worked to scrub away the past and replace it with her new understanding. "The girl he banged in high school came to visit 2 weeks after this pic was taken and he told me I would just have to deal with it." That's not the worst, however: "He was actively receiving and screenshotting nudes from a whore on tinder the same day and lied to me about it." Her boyfriend was at the very least unfaithful in spirit, right? So she went back and rewrote her time with him to make it fit the now. "We finally made it to riverhead to go berry picking (where my car broke down and he just yelled at me)." Yelling at your girlfriend for her car breaking down seems a bit impotent to me. "This was the first time his family heard about me even though we had been TG (together?) since October." He also apparently kept her as a secret, not exactly promising for his fidelity to their relationship. "Great day, but he still sucks." Even a good day was pretty much ruined by this guy. Of course, good for her for reclaiming her past. Yet, there are two strands of self-inflicted misery underlying this story that we probably all do to ourselves. Why pose for fake photos and pretend to have an ideal life for Instagram even when that very day there is conflict that could clearly signal the end of the relationship? Any relationship founded on such a bad private life and such a fake public life seems to be a sickness in and of itself. The optics are not worth the pain, are they? Additionally, editing one's Instagram captions to revise the relationship just reinforces this totally social media centric lifestyle, as if the public record can change her own internal record. From my perspective, these two were obsessed with social media to a destructive fault. But that's hardly new. What do you think?

A man was caught cheating by his girlfriend's best friend after he started behaving suspiciously, as reported by The Sun.

Taking to TikTok to post a video that appears to have now been deleted, Lottie Passco recalls how she asked her pal Meg to send her boyfriend a message from a fake Instagram account to see what his response would be.

Lottie's boyfriend replied pretty much straight away, according to the TikToker.

Sharing screenshots of her now-ex's messages with her 5516 followers, Lottie revealed that her boyfriend and no qualms about meeting up with Meg - aside from the fact that she was “ages away”.

When Meg asked Lottie if she should carry on messaging her boyfriend, Lottie said: “I don’t want to be a mug again so I’d rather find out now than waste my time again.”

Credit: TikTok

In another video posted to TikTok, Lottie explains, per The Sun, why exactly she had started becoming suspicious about her boyfriend and specifically why she started doubting his faithfulness to her.

She said: “The whole reason why we did this is because my boyfriend previously cheated on me and had a Tinder account for like a month or two over my birthday and everything.

“So my best friend Meg messaged him on a private Instagram pretending to be another girl.

“Within an hour of talking to this ‘girl’ he had made a fake Snapchat account so they could talk without me knowing and was sending a lot of inappropriate things.

Credit: TikTok

“The only thing he said to stop them was the fact that he lived far away and not the fact that he was with me.

“I left him instantly and dropped his stuff around at his house, and he burst into tears and all of this, and then I found out that he had a Tinder account the whole of our relationship, which was over a year.

“I’ve found someone new and I’m so happy.”

Needless to say, a number of people praised the social media star for taking the plunge to dump her cheating boyfriend.

One reportedly wrote: “Glad that you got out and that you are better”, with another saying, “I’m sorry this happened, some men are dogs.”

Cheating is a devastating revelation in any relationship, and these days, there are more ways than ever to discover if your partner has done the dirty on you.

Case in point, this man, who claims that he caught his girlfriend "cheating" after a close inspection of the reflection in her eyes.

TikTok user Sam Nunn, who uses the handle @samnunn4, made the revelation on TikTok, where people have been sharing the ways they discovered they were being cheated on as a part of a viral trend.

He took to the app to share footage of a woman who appears to be his girlfriend using a dating app in his company.

Watch the footage below: 

[[tiktokwidget||https://www.tiktok.com/@samnunn4/video/6907840977491283206]]

As the video above shows, he films the woman then zooms in on her eyes, which show her swiping through the profiles of various other men on a dating app like Tinder.

Alongside a sad emoji, Sam captioned the video: "thought she had fun baking cookies today #f*cklove"

Needless to say, after implying that the reflection is evidence that his girlfriend is cheating, many social media users were sympathetic.

"Can you record a video of you kicking her out?" one user said.

[[imagecaption|| Credit: TikTok / Andre]]

"If she can lay beside you and swipe through that app without a second thought, she's done this before. You deserve better," another wrote.

[[imagecaption|| Credit: TikTok / killua]]

Meanwhile, a third simply wrote: "it was only through her eyes did he see the truth."

[[imagecaption|| Credit: TikTok / Fatty_o]]

However, not everyone believed that the video was what it appeared to be.

Another TikTok user wrote: "WHAT KIND OF PHONE IS THIS MY GUY!? The iPhone 25!?!"

[[imagecaption|| Credit: TikTok / Josiah]]

A second similarly implied that no phone would be capable of showing such a strong reflection, writing: "That Samsung Galazy S20 Ultra 5G does have one hell of a zoom."

[[imagecaption|| Credit: TikTok / Dale Atchison]]

A third simply implied that it was all a setup, writing: "So you got that close to her and she didn't close out the page???? Seams [sic] a little fishy to me."

[[imagecaption|| Credit: TikTok / Kobe'sTheGOAT]]

What do you think of the video? Do you think this guy was really able to see his girlfriend cheating from the reflection in her eyes?

Back in ye olde days, it must have been really easy to have a fling with someone. All you'd have to do is make some excuse about needing to do something a few dozen miles away, saddle up your horse, and neglect to include details of the raunchy affair when you wrote home to your spouse.

In 2018, however, there's no chance of that.

People are always Whatsapping and Facebooking and Instagramming and lord knows what else - and any change in that kind of routine (especially between couples) always raises suspicion. What's more, because of how often we take selfies and other pictures of our surroundings, it's so much easier to leave a trail of evidence for things that we might otherwise not want people to see.

So, when one guy had an inkling that his girlfriend, Jackie, might have been messing around behind his back, he made sure to pay very close attention to the messages she sent him. And, sure enough, she slipped up.

The conversation started in a fairly normal (albeit slightly naughty) way, with Jackie sending her bf a sneaky little picture of herself in the bathroom, along with an excuse about why she was texting late.

So far, so plausible. But then it gets a little more suspect.

Jackie's boyfriend texts her back asking for another naughty picture (and, really, can you blame the guy?) but what he gets back is a little more than he bargained for.

Something in the second picture sets off alarm bells in the boyfriend's head. Have you spotted what it is?

If you avert your eyes from the nudey lady for long enough, you'll notice there's a suitcase in the bottom left-hand corner. Now, to you or I, this doesn't seem suspect at all; Jackie has gone travelling, so why wouldn't she bring her case with her?

Well, the thing is... that's not her case. And Jackie's boyfriend knows it.

Nevertheless, Jackie tries to brush off his line of questioning as casually as she can - with a dirty pic thrown in for good measure, of course.

To argue her case further, Jackie prompts her boyfriend to call the hotel and ask to be put through to room 1422. What she doesn't count on, though, is that he'll give her name to the receptionist.

And this is where it starts to get super cringe-worthy.

Ooooh someone's been rumbled! Should've gone with the traditional sext instead of the modern-day nude, eh Jackie?

But it didn't end there. Jackie's boyfriend then went all out and sent her this absolute slam-dunk of a text chain:

So folks, the lesson here is obvious: don't send nudes. Ha, just kidding, nudes are great. No, the real lesson here is that you shouldn't cheat on your other half.

Or, if you're going to anyway: don't send them any evidence of your infidelity.

Ha, no - kidding again. Seriously, though, don't go messing around behind your partner's back. Otherwise, it could be you coming home to a lawn full of trash bags and a story about you on VT. So unless you want me joking about your nudes, I'd take my advice.