My boyfriend of 3 years

Im not sure why im writing on here but I just need to get this out. A few months back, I was at school (I go to college at night) and my boyfriend text me and told me he was going to hang out with some friends. So i was like ok cool where are yall going and he told me. That was fine with me until a few minutes later he text me and says I'll just tell you now, that im going with amber (my 26 yr old cousin). Thats when I hit the fan. All I could think about was why did he think he had to lie to me about going to hang out with her. Right then, I knew there had to be more to the story. He never lies to me. I didnt know what to do so he kept texting me saying are you mad at me? and i ignore him for a little while then I finally wrote him back and asked him why he felt that he had to lie to me about it and then he started this you dont trust me do you? I just ignored that because I wasnt saying yes or no, but at the time no I didnt trust him because he had just lied to me about going to hang out with my own cousin. So I called my mom and asked if my bf had left and she said yes and that they had told my cousin not to go hang out with him because she wouldnt like it if I went and hung out with her bf while she was busting her ass at work all day and then at school at night. So she went anyways and the whole time they were out (they went to play pool) he was texting me and we were arguing. When I got home from school at about 9:45 he texted me and said I dont know if Im coming home tonight (since we had been fighting). So i called him and was like I see what means more to you and blah blah. So a little later he gets home and I hear him throwing my stuff out of his car so that he can take his car and leave. Right before he had got there I had seen that she (my cousin) had sent him a picture of her boobs (naked) on his phone and he had forwarded it from his phone to his email. Wow right then I hit the fan and couldnt think of anything except how hurt I was. So I went outside and went up to him and he was so mad (and i knew he was mad bc he knew he had done wrong) but he was mad and wanted to leave until my mom made him come in and talk to her. The whole time she was talking to him I didnt know what to think. This is the guy that I had given everything up for and I worked and went to school so that I can make more money and help us better ourselves. I did everything for him and I knew everything about him. Our relationship was much more than people thought they knew. We have been through things that no one knows about and I couldnt believe that he would have done something like this to me. So then I talked to him and he just sat there and didnt say anything. He never would admit that what he did was wrong (until we went to bed that night) and he still never said he was wrong he just said he didnt mean to hurt me. But he told me that she had sent that pic to his phone for a coworker the day before. I was livid. I dont care if it was for someone else she knew he was my bf and she shouldnt have sent it to his phone. Then I couldnt believe that he didnt tell me about it and then he went out with her. That was sooo messed up. Well we worked it out, technically he didnt do anything with her. Then about a month ago one of my other cousins told me that my cousin amber (the girl my bf went to hang out with) had told her that my bf had told her if she would give him the time of day, he would cheat on me. That just started it all over again for me. I asked him about it and he admited to it but wouldnt say anything else about it. Needless to say I lost a lot of trust in him because like I said he never lied to me about anything major or really at all. Once again I got over everything and decided to be with him because I loved him way too much and no matter what he did to me I couldnt be without him. But still to this day I find myself questioning our relationship and if I trust him or not. I really dont trust him and for some reason I always doubt myself and make myself feel like Im not the one he wants. I say stuff about that night all the time and he gets mad at me about it and tells me not to say things like that but its just my way of getting it out and i dont know. I want to leave it alone and put it in the past but for some reason I keep letting it get to me. I love him more than anything in the world and he loves me too but then again I think if he loved me he wouldnt have hurt me. I would never do anything to jeopordize our relationship and I know that two wrongs do not make a right. I just cant help but re live it over and over and wonder if he will do something like that to me again. Im pretty sure he did it because he was lonely. I went to school in the morning, worked till 4 then went to school at night from 5 to 1030 at night. And he worked too so we didnt get much time together on the weekdays. He never would say that was the reason but he did ask me if he was going to get to see me more. But even if that was why he did it, that does not justify it. But I just needed to tell someone else and I hope that someone will reply even though I just wrote a book. Sorry. But someone please share a similar story or just a little bit of insight.