Him, me, girls.

My boyfriend and I have been together for over a year now but I still have problems trusting him. He use to talk to a girl and he never told me about her, and when we were together he use to never hold my hand and stare at other girls. Things are better. He holds my hand, hugs me, walks with me. As far as I know I'm the only girl he talks too. I use to be okay with myslef and then when did this question number thing and I asked him if there was one thing he could change about me, what would it be, he said my breast size. Even now to this day I have problems with myself, wishing I had more than what I have. The other night me and him were talking and he admitted to looking at other girls boobs but he try his "best not to". I feel like he doesn't want me anymore because he never says intimate things and we never talk about intimate or sexual things anymore. Me and him talked about it again today and he said he wanted to figure out how to help me not be so anxious and upset that he looks at other girls breasts. There are times when I will look at other guys stuff but the differnce is I don't go out of my way to where he does. I don't even want to because I don't want to think nor see anyone else but him, but when its noticeable and its something that just is there I feel its only human nature to look at the things that might stand out. What do I do? What do I say to him?