I Found My Best Friend’s Boyfriend On Tinder And He’s Trying To Cheat On Her, What Should I Do?

Amy is my best friend and it’s always been a complete mystery to me why she is always single. She’s 34, thin, reasonably pretty, employed, and a good family girl. She has a big laugh, lots of personality, and loves sex. Sounds like wife material, right?

Anyways she’s been in a new relationship for about a year and I think she is going to marry this guy. In all ways he is just good enough. I wouldn’t be into him, but whatever, I am happy she is happy. And she is happy. They are talking about marriage.

The problem is that I’m pretty sure this guy is trying to hook up with random girls on Tinder.

Let me explain. I made a dummy Facebook account for my Tinder because I just got out of a very long, very shitty relationship and I am very much not interested in dating, but I miss sex. So that’s what my Tinder is for. I have a couple body shots on it, but you can’t see my face.

While I was swiping, I came across someone who looked and awful lot like Amy’s boyfriend, but like me, his face was obscured (though, from what I could tell, I would guess it’s him). He has a pretty unique name, and the name and age matched. The tone from what he said in his bio also matched the way this guy talks. He said, explicitly, that he is looking for NSA sex. We matched. He messaged me, “hi.”

I don’t think it’s completely out of the question that it’s a big coincidence, but that makes it harder to figure out what to do. One one hand I wonder if I should message him and pretend to go along with what he is saying, long enough to get proof that it is Amy’s boyfriend and then tell her? I really, really don’t want to do this but I wonder if I am obligated to. Unless something goes off course, my friend is going to marry this guy and he is going to cheat on her for no reason, forever, until they probably have an unhappy divorce.

On the other hand, is it really any of my business? I don’t want Amy to shoot the messenger and hate me because I exposed her boyfriend as a weird cheater. I really don’t want to get in the middle of this or be involved in any drama. But I wonder if I am obligated to, is this really something I can keep quiet about or will I regret it if they get married and it ends badly — and I could have given her information to avoid that fate.

What should I do?