My boyfriend’s type is girls with chests 3x bigger than mine and he looks at other women’s chests-what do I do?

I was friends with him for 4+ years before we started dating so I’m not really ready to break up with him yet. he’s amazing at accountability and always acknowledges my feelings and never minimalizes anything I bring up to him. he insists that he wouldn’t change anything about me, but it’s hard to believe it because of his words and behaviors.

hes told me that he prefers girls with a larger chest, and any time he sees a girl with a low cut shirt or a c cup or larger his eyes flick down and then back to her face or away. i told him it makes me feel terrible and insufficien, and he tried to reassure me and told me hes working on unlearning the preferences and unrealistic beauty ideals hes learned from his prior porn addiction but I really just can’t look at him the same anymore. I feel disgusted with him and with myself, and I don’t know what to do to stop feeling like this because obviously he’s dating me so I’m at least good enough.

additionally, we’re going to be doing long distance for the next 3 years and I’m so worried he’s going to get drunk at a party and cheat on me with a woman who actually fits his type.

ive never been insecure about the size of my chest (I’m a 28B) but whenever I’m with him I just feel so embarrassed and insecure and feel uncomfortable being seen by him because I feel that internally, he’s disappointed and that’s why he’s looking at other women.

i also already had a whole conversation with this about him, jn which at some point I was spitting pure vitriol at him and calling him a pig, and not once did he criticize me or try to excuse his actions. he’s trying, I just don’t know how I can stop feeling so so hurt about this