My first boyfriend did the same. Dumped me at 15 because I didn't want to have sex, so he started fucking some trashy obeast at his work. He worked at McDonalds, so that probably gives you an idea of the level of trashiness lol. Anyways, I ran into him at a party when I was 18 or 19 and he was drunk and sobbing about how leaving me was the worst thing he ever did and he was so sorry blah blah blah. After that he tried adding to me Facebook and I promptly blocked him. I guess he ended up working for Canadian Customs at a bridge crossing. My parents live in a border city and a few years ago when the dollar was good, they used to go to the States once a week to get gas and a few groceries. They always declared everything when coming home (not worth getting into shit with Customs for a few muffins or some dog treats) but whenever they passed through the gate my ex was working, he would always send them for secondary inspection, just to be an asshole. One of the guys who worked the secondary inspection asked my parents, "I've been seeing you two in here more frequently. What's going on?" My mom told him that the guy working the gate was my ex, and whenever my parents went to the gate he was working, they got sent for further inspection. Secondary inspection dude seemed annoyed and supposedly said, "just go. I'll have a word with the supervisor." He was pissed because my parents knew better than to bring contraband across the border, and he was wasting his time searching their car for a petty grudge. I just thought it was hilarious that after all these years, my ex was still bent out of shape for no reason - he was the one who cheated on me. I think the fact that I ended up better off without him really upset him, even 10+ years later.