Hello Logan and Deck,
of course everyone's experiences are different, but here are my answers to your questions:
1) I can't quite remember, but we weren't dating that long before he disclosed. Perhaps 2 months?
2a) He happened to disclose in an angry outburst, and I think I was crying at the time already. I felt terrible for him and all the pain that he went through. I just wanted to let him know that I love him and that it didn't change anything for me in terms of what I felt for him, so that's what I did. And that I'd be there for him and support him.
2b) Why I felt the way I did? That's really difficult to answer! I'm sadly no stranger to sexual abuse, so I think that may have had something to do with it - as in, I didn't freak out and could somewhat understand his pain I think.
3) Of course I think something must have happened specifically to set him off, but the said angry outburst wasn't actually aimed at me. It was more a rant on his part about how badly his life was going (that was his take on it anyways). It didn't seem that there was anything that happened between us that specifically brought it on.
And it wasn't directly related to sex I don't think. At that point we hadn't gone "all the way" yet in the relationship. Of course, that could have been part of it, but I'm not aware of anything specifically happening beforehand - not that I picked up on at least.
But again, that's just one experience, I'm sure things were rather different for others. I hope this is a little helpful at least. =)