I have to agree with Scarlett, here. Dog and I knew each other for 15 years before we even kissed, so there was a huge amount of trust in place. I think that is a large part of why I can let go with him in a way I never have before. Not that you have to wait that long, by any means, but we were friends first, then lovers, then we got into kinkier sex. It was a building process.
Also, keep those lines of communication open once the sex/kink starts. Talk when you are dressed, not in the bedroom . . . ok, not in a sexual mode, since we tend to do it all over the house. And, for me at least, having his friendship when we are not playing is huge. I don't/can't do total power exchange--too much of a control freak, I guess, although I would really like to spend, say, a weekend totally at his command. But we are friends, first, and that's what makes it work for me.
Good luck in your search. I can't imagine how hard it must be to look for a kink partner, since I got lucky enough to fall into this-hard.