its hard to let go

About a year ago I started dating my current boyfriend. We met online and when we met we really hit it off. Everything for the first month was great until we ran into a little snag in the road were we almost broke up. We talk everything out and things went back to normal but the fear of it happening again stuck with me. This has happened in a past relationship were everything would be fine then the next day we break up, but not by my choice. And I had found out that he had cheated on my once and then another time we had gotten back together he already had a girlfriend at the time, so he cheated with me. the whole thing  had gone on for 3 years and I was just able to finally stay out of it about 6 months before I met my current boyfriend. But after the little hick-up in the start, I am always thinking that it is going to happen again or that I will be cheated on again. The guy I'm with is nothing like my ex. He's sweet, kind, makes me always feel beautiful and shows how much he really loves me. But he also likes to tease me about girls, he used to talk alot about ex girlfriends and hook ups and he is still in contact with an ex that used to dump him then get back together with him. I trust him but then at the same time I know saying it is not making it true. Because if I really did then I wouldn't be worried about being dumped or cheated on. I have talked to him and he has stopped talking about past relations and he doesn't tease me near as much as he used to about girls. I still don't like that him and his ex talk but they don't talk alot or very often and they are friends now plus I can't tell him who to and not to talk to. But I need help when it comes to trust issues. Alot of help. :(