I'm going to pretend to be gay to break up with my ex girlfriend
Why would you pretend to be anything?
If she's jealous, she'll definitely realize she has feelings for me
You can break up with someone if you want to. But don't misrepresent yourself to manipulate someone.
It's just a joke and I'll go back to being straight.
I would not joke about something serious like your sexuality. I think that it is wrong to pretend to be something that you are not.