What Did I Do Wrong?

I met this guy who's like 29 and when I was 18 and he was great and fun and the first one I did anything sexual with. He moved across country for work and I started college and we'd been doing the long distance thing. One day he says he loves me and wants to marry me. I cared a lot about him but thought I should finish school first. He kept saying it was okay and that he'd visit me at school, but never did. He asked me to come out there but I couldn't cause I was broke and hoped that he could visit me. He started to seem a little distant and when I asked if there was something he wanted to tell me he said, only, "I love you."

After not showing up here when he promised he would, I told him it was okay, but instead of being relieved I wasn't mad, he picked an argument, now claiming that because of work it would take him months to return. He called me to apologize, asked me not to see anyone else while he was gone. After a few days, he seemed annoyed when I called him to say I loved and missed him. Again, I asked him if he wanted to tell me something. He said " I need you to have faith in me." I told him I did. Later, we got into an argument after I asked him when exactly he was going to visit me. I'd always been the one to make up first, but I wanted to give him a break for a few days. He again asked me to have faith in him and added, "I need you to be patient." I wanted to but told him I felt there was something he wasn't telling me and I couldn't continue without knowing what it was. He said, "work is keeping me really busy,but I love you. I'll explain everything soon." Then he went silent. I wrote him/called him, but nothing. Two months later I found out he was getting married to someone else the following week. I called him and he didn't know I knew. He was sweet but kept exclaiming "it's been a long time." He didn't offer the info so I told him I knew. He didn't apologize or tell when it all started. He turned angry and demanded to know who told me. He started naming his friends and family as if ordering me to tell who told. I told him the only thing that mattered was why he didn't tell me. Still angry, he asked me, "What else do you know?" I didn't answer him. Then he switched and became sweet again and said, "that's what I was trying to tell you." What did I do wrong with this guy? Why did he do this? What should I do? His friend just said (when I told him I knew) that he really did care about me and that he met his now wife only four 1/2 months ago. What went wrong here?