For the past 10 months I've been in a sexual relationship with this guy. He used to have a crush on me but I didn't really see him as boyfriend material (glad I didn't now). If I don't want to sleep in my dorm (college student), we'll have a sleep over and just watch tv, and we talk EVERY day. We'll hang out, he'll bring me food or medicine if I'm sick, really sweet guy. I admit that after 10 months, I have gotten a little crush on him and I thought he felt the same way about me. So yesterday, on the popular page on insta, I find this girl who is his whole girlfriend. They've been together off and on for like 2 years. I don't fool with no cheaters by any means, and I don't plan on foolin around with his lying ass no more, but do I tell her what has been going on???