I did once. Had a fight with my new girlfriend. My ex still wanted to get back together. We met up and had just passionate animalistic sex. Funny thing was later that night (New Years) I patched up with my current girlfriend and had sex. Maybe not my finest day but it was fun.
No. That's probably because I broke it off with both of them. Well the first one was a mutual breakup. His loss though. He tried to get back with me 5 months later and I already had another boyfriend at the time. And the second one I was never in love with in the first place.