OK WHAT IS WHAT? How can I tell if my ex is bi or just flat out gay?? Im beyond confused.:/?

Ok so I dated this guy about a year ago. We fell in love and when our relationship ended we both had feelings for eachother. We did sexual stuff together but no sex. He came out that he was bi and our relationship soon ended. I didnt care if he was bi, I really didnt care at all, but our relationship ended because of me. I lied to him and im not gonna go into that lol but anyways. He has dated guys ever since we have broken up and he hasnt been with any girls. Im confused because he will say he is gay and then five seconds later he will say im only bi for you. A part of me believes that he really is just bi and is pretending to be gay. Even his mom said she knows that he is not fully gay even if he sais he is sometimes. His friend said that the way he looked at me was totally obvious that he wanted me and was still madly in love with me. When we are together, which isnt often he just acts so into me. He flirts with me, teases me, finds an excuse to touch me. He likes to wrestle me and just be mean like that. He looks me deep in the eyes and he looks really shy and happy, like his face warms up when he sees me. I see these things, and so does everyone that I talk too. I dont know what to do though because he will sometimes downplay it! I mean maybe he really is just gay. I dont know. I mean would it make since that he could just be bi with me??? lol. Im really confused, and I hope theres a chance for us. But if he is actually gay and not bi then I need to let him go. So I really need your guys help with this:) Thanks and sorry it is way to long lol