If that's their attitude they're not going anywhere fast in life. Doesn't matter if he has great art, a shit attitude makes a shit person so stop wasting your time on them especially when they're clearly obsessed with making other people's lives hell. That act alone should speak volumes about your ex and her boyfriend to potential or currently existing watchers of theirs who may carry even one iota of reason. If for whatever reason their bullshittery manages to find it's way to you when you've done all in your power to avoid them, just report for harassment and move on with your life.
Well yeah the harsh guys are right, I just thought I'd add some balance. The not sure ones are probably just trolling because this kind of is a petty issue. Out of curiosity can you link me to the guy who's so "awesome"? I'd like to judge that for myself. I'm not about to get all in his face for your cause or anything.