Do you think it's OK if I date my ex's favorite athlete?
Well, why do you want to date this person?
I think that he's a very fun person, and I want to have a great time with him.
It is okay to date other people when you break up with someone. It is normal but you should not date a person just to rub  it in especially dating your ex's favorite athlete. It is very petty.
Who said I was trying to rub it in. I want to.
I mean, if your dating him because you want to date him, that's great! I'm just saying don't date someone just to get back at someone else. It's fair to everyone to be honest about who your dating.