psychoslag
ex girlfriend who insists on making it obvious that they're sleeping with other people with the purpose of trying to cause they're ex pain mentally. Also constantly trying to show that they're extatically happy without they're ex, often laughing out loud when they're within earshot/sight and constantly trying to belittle them and turn all their ex's friends against them.
My ex is such a psychoslag, she'll sleep with anything just to try and make me jealous - how pathetic is that, who would want anything to do with a psychoslag?