don't worry about your abusive narcissistic ex taking a new GF. Read this to understand she is YOU. Only u r free from the misery and abuse!! Of course it sounds all snuggly; endorphins are wonderful things. You are wise to focus on YOU and your children...yes the children he now fails to engage with oR support. No point in advising new GF ...in time she will know the Horror.
Yes. Otherwise they'll get deeper and deeper into it. At lease they have a fighting chance if you tell them.
Please NO!
Tell him to go and leave you alone.
Be careful if you do, the narcissist can be a monster to anyone who hurts their pride.
call or go over and speak to him in person
That the supply of oxygen for the fire
It's not best to tell him after a while so be straight and tell him
A - How do you know they are narcissist? B - Why do you assume that the friend doesn't already know? C - Why do you think they might want to know? D - Is it any of your concern? If you can satisfactorily (and honestly) answer those questions then yes, tell the friend, otherwise leave the matter lie.
If he or she dates people of the same sex.
Yes, but only if he got something out of it.
That it didn't work out. The rest is none of their business.
Speak to the manager. He or she should be able to tell you who you need to talk to.