My husband jumpscares EVERYONE, including our 6 month old son! His version is tame compared to what your ex husband did. He doesn't hide around corners or anything like that (most of the time). He just waits until a suspenseful part of a scary movie, or even if we're not watching a movie, but if the room is silent and I'm concentrating on something, then he does this loud, deep "RAWR!". It gets me almost every time! It does get old and annoying, but at least he's not malicious about it, and sometimes it's still funny to me lol I hope you can find help getting rid of your ex husband! Contact a priest! Keep us updated and keep yourself and your son safe!