my fiancé was raped and I don't know how to handle it..

Hey guys, I'm 20 and my fiancé is 23. He is a wonderful man and very loving. He was my first, and he's had quite a few relationships and one night stands but he lost his virginity when he was 7 and it was due to rape. Like any couple we have fights now and then but this is the first time he has brought up his past in an argument, I feel so sad for him and angry at everything he's been through and what's happened to him. I don't know what I can do for him, it was so long ago and he's still hurting from it and a lot of other things. I want to help him but it's not like I can change the past and undo what happened to him. What should I do? I feel sad thinking about all this:( and also, as for the picture, no he's not actually wishing that on me, he just said it the wrong way. I just want to make him feel better and end his pain...