How long will this hurt?

I went out with a guy for about a year,about 10 to 11 months into the relationship some of my friends started telling me that he was messing around with another girl, I asked him about it and he told me that he didint cheat(he told me that they were just friends and he didint like her like that) anyways he keept saying that he loved me and that he wouldent do that to me and just always denied everything. well for some reason I decided I would believe my boyfriend (wich I now realize was the worst thing I could of done)so anyway I stayed with him for a little bit after all that and just ended things with him bacause things just were not the same anymore so I just stoped talking to him. a couple of months later I found out that he is going out with that girl and that she is now pregnat!!! I felt horrible, I felt even worse than when we broke up, I mean I had stopped hurting a couple months after I broke up with him, and it didint really hurt that bad, but now I just feel horrible because I lost so many friends because of him I will never forgive myself for that. ok so now I live in a different state and it makes me fell a litthe better cause I wont bump into him anywhere but what dosent help is that he keeps calling and texting me, I have only talked to him once after the break up and I hate how he just acts like nothing happened. so a little bit after moving I met one of my brothers friend who is a really cool guy and I like hanging out with him, he told me that he likes me (and I like him too, we have actually kissed a couple of times) but I am still so confused, I dont know what to do I am still very hurt, I feel like I can never trust a guy again, I dont want to mess up again I told him I was not ready to go into another relationship and he told me he would wait untill I was but I dont know what to do, im scared I guess,I dont want to mess up again. what do you guys think I should do? I am really confused and dont want to get screwed over by guys anymore.