These sexual blackmailer types and their enablers, are scum and their scheme needs to be exposed. I would guess that most of their targets at first didn't even know what they were getting into by having the sex. But then later they figure it out, when the blackmailer makes a comment in jest like "Now you wouldn't want your wife to find out about that, now would you?". The guy is owned from then on, and he never tells anyone about it, allowing the blackmailer to even reuse his scheme on the friends of the target, who would normally discuss anything in the world between them.