Good questions...Rourk does seem very self sufficient until that point doesn't he? But he trusts Mike, one of very few people in the whole world at this point. He seems to have put his entire past behind him, so he cannot go back to his past work in the quarries. He also makes it clear that he doesn't want anyone to know who he really is, or where he is. They just call him Red. He asks Mike, because he trusts him, and because he wants anonymity and Mike has the connections to make it work.
As for the kinky sex thing, well, I hadn't thought much about it, but I think that Dominique had to be broken. She had set her mind to have no men, and suddenly she was drawn to this one. It was going to take a lot to break a lifetime of expections. He needed to be a thunderbolt in her life. He was. Still is. Always will be. The real strange stuff comes later..