I'm married and faithful for 17 years but had 2 affairs when manic. One was with someone I met at a local 12-step program (or 13th step, as they say...), the other guy I met on MySpace, which was pre-facebook. Luckily I never got any std's, cause it was all unprotected as well. These were relationships that went on for months while I was escalating, not one-nighters. I later investigated the MySpace guy since he was not local, and found out he had a prison record. It's very risky and I know how you feel. Maybe you can try to knock yourself out with exercise? I'm not a fan of internet porn and I guess the downside is, it might be a trigger to more sexual behavior, but if that could substitute for the real thing it might involve a lot less risk...