my ex and I had a very bad breakup which included him cheating on me with a girl and then lying about it and telling everyone he dumped me before he got with her. we both are in college and he met her through his club. when i found out about his cheating instead of saying sorry he simply blamed the whole situation on me and said it was my fault for ruining our relationship. the semester ended and summer started and he and i started to see each other and we started hooking up, all throughout summer he told me what he had with her was just a fling and that it wasn't serious and that he still loved me. now the academic year has started again and me and him were still fooling around and i thought he was starting to love me again but then one night i saw him and her walking around and when i asked him about it he completely denied it. even now we have the worst fights and he denies anything with her while the world tells me he's official with her. I feel so bad about about myself and still love him a lot and am just so confused as to what I did wrong. I can't move on from him as he lives in my building and not seeing him isn't possible, i dont understand how he can be with me and her at the same time while telling me he loves me. i dont know what to even do anymore. everyone has been telling me how she isn't even a nice person and told everyone she's going to get with him when me and him were still official. I still dont get why he even cheated and why he can't own up to it. im just confused why tell me he loves me while being with her? and now why lie to her about me?