‘Girl tell his parents’: Woman discovers her boyfriend is cheating on her with his own sister and TikTok is grossed out

Being cheated on is a horrible way to end a relationship, but imagine how much worse it would be if you found out that your boyfriend was cheating on you with his own sister. Well that’s exactly what one woman on TikTok claims to have experienced, and she’s shared the details in a video that has since gone viral.

Katelyn’s story starts out innocent enough. Her and her boyfriend sound like a pretty solid couple as she explains, “we were the type of couple that was like ‘oh my god, they’re going to last forever.’” But unfortunately this perfect relationship was simply too good to be true. 

For some reason, the boyfriend’s sister took an instant dislike to Katelyn. The three all went to the same school and the sister badmouthed her to anyone and everyone, all the while the boyfriend did nothing to stand up for his girlfriend. In fact, he told Katelyn that she was “insane and needed to get over it.”

Fast forward to the day it all came out and Katelyn was at her friend’s house when she noticed that her boyfriend’s location was showing him at a local park. So Katelyn and her friend decided to do a bit of stalking and head to the location themselves to see if anything improper was happening.

It was worse than cheating

Unfortunately for Katelyn, her boyfriend was cheating on her, but it was who he was cheating on her with that turns this story from a bad to downright unthinkable.

“I see them doing something crazy that you should never do with your sister,” without going into detail Katelyn gets the point across pretty well. After witnessing such a shocking scene, she and her friend confronted the incestuous couple, “when I tell you they were shaking.” The boyfriend even tried to deny it despite being caught in the act.

People on TikTok were flabbergasted with Katelyn’s nightmare story, most were in outright disbelief. “Sister???? As in same mother and father??” Exclaimed one incredulous individual. “H-h-his s-sister like they came from the same person…” wrote another.

Katelyn’s story is certainly one of the more wild cheating stories that have been shared on TikTok over the years. To add insult to injury, she claims that after she dumped him, he went around accusing her of cheating on him. Commenters suggested she tell his parents or tell somebody, but judging by how many views Katelyn’s story has gotten on TikTok (7.3 million at the time of writing) it’s likely the news will get back to them very soon, if it hasn’t already.