Kissing cousins

I've been with my boyfriend for 3 years. He confessed to me that he use to have sex with his first cousin. When he initially told, I wasnt shocked, because I always thought that they were too close to be cousins. The first day I went to his house he had 5 pictures of her on his dresser. Then on his myspace page she's the only girl in his albums. He didnt even put up a picture of me. This is all before he told me about them. I thought it was strange but I thought I was being paranoid, so I never mentioned it to him. But after he told me, I told him that I wasnt comfortable with the way they communicated with each other, and then I wanted him to take all her pictures down. He took all her pictures down. But he refused to stop speaking to her. Now, I looked on his my life account and her picture is his profile picture. I couldnt believe it, he said that he doesnt know how it got there, but I dont believe that. So to make a long story short, I ended the relationship. He said theres nothing going on with them, but I dont believe that. Am I wrong for not taking his word over it. Is it normal? Am I crazy, because to me, I feel like their still messing around and that he's in love with his cousin... Please help me..