Segnosaur
Penultimate Amazing
You're right in that 'entrapment' must involve someone doing something they might not otherwise do. But then, such actions should be taken in context.Is entrapping the right word? In police work, a charge of "entrapment" is pretty specific, and the victim has to show that s/he would have been unlikely to commit the crime without police enticement. As such, when considering whether hiring a prostitute to initiate/spur on divorce proceedings is "entrapment", we also must consider the character and motivations of the husband.
There is a difference between a wife setting up a husband (via a hooker) who "naturally" (for lack of a better word) cheats even when times are good, and a wife setting up a husband after the marriage has failed even if the divorce isn't final. In the second case the husband might not have cheated if he and his wife were still getting along (in which case hiring a hooker isn't showing that "the husband is bad", its more a symptom of "both parties recognize the relationship is over except for the paperwork".)