I'm also a partner of a CSA survivor. The most helpful thing I did for myself was learn all that I could about what was troubling my boyfriend. I wasn't out to find him a cure, or get involved in his therapy, but it helped me empower myself and feel more comfortable, to know what was going on and why.
There are some great articles you can find on this site, using the drop down menus at the top of the page. There are also links to other web resources and books (if you buy books through the site it helps us out).
I don't think there is "an answer", I think each survivor and each relationship needs a slightly different set of answers, and the best way to find the answers you need is to keep asking questions.
We're here for that, and for support and encouragement too. I do know that it can be done, he can heal and your relationship can heal. My life has changed so much just in 18 months, I wouldn't have believed it.