Help me please

Erica
Okay, so my boyfriend kinda cheated on me. Kind of, by this I mean we ran into some issues, and kind of broke up, but we were still kind of together, I thought we were still in a relationship because he said he was trying, and I was trying, and I asked him so many times if there was someone else and he said no, anyway, there was someone else, he was sleeping with her, and kissing her, and telling her he loves her, and anyway he broke things off with her when I found out (btw I'm pregnant) but he said that he thought we weren't together. So I guess maybe it was a misunderstanding? I mean obviously we were having problems, but I thought we were together and working through them, and I never broke up with him, and he never broke up with me, like it never officially ended, we just kinda separated for a little while, but we still talked everyday, and said we loved each other. 
Anyway, I believe that he left her, and we're working on our relationship, but I'm still having a lot of trouble with trusting him. And lately he's been talking to a lot of girls, and I just really don't trust him talking to them. 
Like if a random girl added your boyfriend on Facebook (they don't know each other) and he said hey to her, and started a conversation either her, then added her on snapchat, and they talk on that now too, would you be worried or scared? I don't know if I'm being crazy for feeling this way or not. 
I think he shouldn't be messaging girls that he doesn't know on Facebook, if he knew them it would be different, but he's been talking to a bunch that he doesn't even know. 
I really want to work things out with him, despite what happened, I just want advice please