Advice ?

Cynthia • 20, engaged and ttc.
Okay , so my fiance has been acting weird lately. Well the other night he went drinking with his friends and texted me maybe 3 times from 3 pm to 3 am. I asked him why he ignored me and told me he did it on purpose because he didn't wanna hear my mouth. I never once even attempted to talk shit to him . I called him and he didn't answer so I texted him and told him I loved him goodnight That was all . I'm really starting to feel like he's doing something . Like cheating on me. He just tells me I'm crazy and acts like I have no idea what I'm talking about. Well tonight (he told me he ignored me on purpose a few hours ago) I sat there for about 2 hours debating on whether or not I should just leave. So eventually I told him I was breaking up with him because he was doing something he shouldn't be doing. And he sat on his phone the entire time I grabbed my belongings and left his house. Didn't even stop what ever it was he was doing on his phone to ask me why I was leaving. I don't know what to do . I don't know if he is really cheating on me or am I really just crazy. But he didn't even attempt to stop me ?