Pen and Tim, a Gay Couple, Have Been Dating for Several

Pen and Tim, a gay couple, have been dating for several months. Pen finds out that Tim has been cheating on him. If Pen is like most people, then which of the following will have the biggest impact in terms of determining whether or not he becomes jealous?

A) Whether or not Pen thinks that he is similar to the person or people with whom Tim has been having the affair
B) The number of people who know about the affair
C) The number of times that Tim has cheated on Pen
D) Whether or not Pen thinks that Tim will cheat again