Multiple partners, how to?

I'm starting to realize that all the chatting with Doms on other web sites that I engage in has to do with my very lively curiosity about having more lovers.
But there are three things I am at a complete loss to figure out:
1) If I want to do D/s, how can I do that with someone I don't know--it seems so risky and difficult to meet the right person--part of Z's great appeal is that I totally trust him(only we just don't have sex enough!)
2) How can I have a D/s relationship with two men and keep that secret(as in, secret from Z)?
I'm thinking multiple marks, for one thing.
3) If I'm not looking for D/s, but for some cool sex partner/friend that I can like and trust, how do I meet that person--and what should my criteria be?

After so many years of being married, this is all new to me--help!