A REALLY MESSED UP THING!?

And that's the reason why you can't be friends with an ex you just recently broke up. It's obvious that you have not completely gotten over your ex, that's why you had a strong reaction to his new gf. If I were you, I'd remove him off your facebook. It will make your life so much better not knowing what he's doing. And he will not know what you are doing. Your ex seems like a sleaze bag trying to get attention from you anyway, so don't give him that attention.