I tried but it didn't work. We were in our 20s. He told me he had been abused by his uncle, that he "had been bisexual" and that he loved me and wanted to be exclusive with me all in the same night. We had never been intimate, but he thought we were heading that way and he said he wanted to be completely honest with me. He said this is something he's ready to deal with now. That I made him want to fix what was broken. We both cried. I think he was having a breakthrough while I was having a breakdown. I told him I needed a few days to think, but I already knew...
For about a week, we were still enjoying each other's company, ignoring the elephant in the room. One night, we were at a restaurant, and some of his male friends came over to our table. When he introduced them - one in particular, I was instantly suspicious of their relationship. I didn't say anything. Pretty much every man he made eye contact with after that made me a little antsy. I knew it was doomed. I couldn't imagine living like that -- putting so much of my mental energy into someone else's possible failings. I couldn't imagine having a son with him, then being afraid to leave them alone together. I had outrageous worst-case-scenario thoughts running through my head. All I could think about was "that wasn't a confession he told you, it was a warning." I just knew I wasn't the one for him. I never said this to him, but truthfully, at that time, I didn't have any faith that he could be repaired. My fault, not his. I loved him with all my heart, especially for his integrity, but I had to let him go. I told him we could be friends, but he said he needed more.
Seventeen years later, we run into each other every now and then. He has been in some kind of therapy to address his abuse and its "residue" on his sex life. He finished law school and is a very successful (alpha male!) attorney, married (to a woman) and they have a daughter. I'm extremely happy for him -- downright PROUD of him for all he has accomplished in life. Still, I know I couldn't have been the one to help him get there.