How Can I Help a Male Sex Assault Survivor?

It’s a long story, but basically my fiance and I had an argument on the weekend when I brought up the subject of gay rights. He told me it’s great that gay men and lesbians can get married, and it sucks that they still face violence, but he doesn’t want to hear about gay men. The thought makes him uneasy, even though he realizes that it’s not like they can help it.
He did tell me once (quite some time ago) that he felt uncomfortable about gay men because someone had hit on him when he was younger (he hadn’t gone into detail), and he felt really scared at the time, but I must have not been thinking particularly clearly that day, because I piped up about how unfortunate it really is for those suffering because of homophobia, and the harm caused by false beliefs like that gay male= child molester, and I obviously touched a nerve.
Turns out his cousin had repeatedly touched him in a sexual manner and made sexual comments towards him when he was about 11-14, and every time he thinks about gay men, his mind goes back to that and and how he felt, and those feelings (a male sexually assaulted him, and on some level he’s scared of it happening again) drown out what he knows is true (that being gay isn’t a choice, that gay men as a group didn’t assault him).
I realize that when he says “that’s nice for them that they can do_________, and terrible that _____happens, but I still don’t want them near me”, that’s a hurtful comment no matter what happened to him, but what he said reminded me of how I felt after a guy I went out with raped me.
Straight men honestly frightened the hell out of me, and even heterosexual kissing made me feel disgusting, like I was going to be sick (even if it was only another couple I saw kissing). I knew that my feelings were incorrect, but that didn’t stop me from experiencing them.
I’m kind of mad at myself now, but the way this dispute ended was I almost started crying and told him that I got over how I felt about straight men after I was raped, and that what he is saying is harmful to a large group of people who he’s never even met. So I was now remembering my assault, he was thinking of his, and we both ended up holding each other until we both felt calm enough to apologise for reminding the other of their experience or saying that they should get over it.
My fiance’s sensitivity and understanding were a BIG PART of my recovery and the fact that I can now have a healthy sex life without wondering out loud if he thinks I’m a slut. I’m a big proponent of LGBT rights and equality, but I realize that this caring, sensitive man is not the enemy, and the conflict between what he knows and what he feels hurts him.
I just wish I know how to help him overcome those feelings.