I don't see any negative connotations to adults having sex with who they like, when they like, for whatever reason they like.

People can be non sexual whores for many things having nothing to do with sex; Money, promotion, shelter, boards, etc.

Hell even "legitimate" non sexual million dollar models are a whore to the camera for a living.

BTW... if you live in a country, state or county where prostitution is legal then where is the line, and who decides where it is?