I've heard about citizens' arrests for a long time. I never know the actual reality. I mean, when are you actually allowed to make a citizen's arrest? Let's take a gander at what Wikipedia has to say:

Most states have codified the common law rule that a warrantless arrest may be made by a private person for a felony, misdemeanor or "breach of peace". A breach of peace covers a multitude of crimes in which the Supreme Court has even included a misdemeanor seatbelt violation punishable only by a fine. The term historically included theft, "nightwalking", prostitution and playing card and dice games.

Sure. Good luck to you if you decide to play cop and run up on a dice game.

But that list doesn't seem to include "withholding sex" as one of the offenses for which one can make a citizen's arrest, so it looks like this dude's legal history didn't do him much good.