Michael Cohen.
I suspect Michael Cohen used his position as President Trump's lawyer. In such a position, I suspect he conspired with Stormy Daniels to extort money that they would say was for a non-disclosure agreement. Some of that $130,000 hush money Cohen would pocket for himself. More would be extorted later. I believe that Cohen was attracted to Daniels, which was a big motivation for Cohen. I hope this will be brought out next week.
I think if they DID have sex, it would cost Trump a lot more than 130,000. I think all she had was a picture and a threat.