Backstory - ex who dumped me messaged me, really mad, saying “don’t talk to my friends again bitch. What the fuck is wrong with you. I’m dead fucking serious. I know you messaged (his friend)” I said “I messaged him ONE TIME. it was a while ago.” He blocks me. Says sorry, saying an hour later “I’m sorry for saying that. But I’m serious though don’t message my friends” we exchanged a few words couple days later, he says “don’t message my friends *thats crossing the line*” what does “that’s crossing the line” mean by him?