RunningOnEmpty, words my loving supporter could echo certainly, my heart reaches out to you.
Please do not be hard on yourself because you have training in one area of psychology but found it difficult to understand the issues with your survivor. I have read many accounts of those who have training in fields surrounding male csa/asa as well as in counseling sexual disorders and they found it difficult as well to identify specifically this issue with their patients as well.
Please keep those strong boundaries. Go about your day but do not ignore him, when he is trying to connect with you, connect with him and a bit more. Remember also that sometimes a survivor needs to hear that his actions or words hurt you. If he feels you are an emotional tower, he can assault it viciously. Expressing how you feel hurt or sad can help him to begin to feel empathy. That empathy can then be turned inward, helping him to find the parts of him that he has dissociated from in trying to avoid the abuse. Empathy, such a powerful emotion, helps survivors to want to begin and maintain recovery. An amazing lesson I got from my supporter was her clear view of balance in her, work, worship, relationships, me and family.
My best to you, the answers are not simple, "surviving" as a supporter is a great undertaking. Please know that supporters are viewed in much regard here, you are appreciated.