mckell given my status in life i have no authority to preach on legal stuff, blah blah blah. you have got some tricky situation there!
imo, the best would be to leave. but you gave some good reasons for not leaving. in any other situation i would suggest it.
idk that is up to you.
BUT remember, if he is a true narcissist, he will not change his opinion. to do that would be like suicide, basically he would be undermining all his security.
to admit he is wrong, is to come to terms with his insecuritys and they are crap things.
i knew a narcissist once, and one day i blew my top with her. i yelled, and told her that she was manipulative, that she used me and i hated her.
she carried on trying to persuade me i was wrong. but DONT let them, she did all she could, but i was grounded enough to realise my opinion was right, and i needed to get away from her before she hurt me more.
in 15 yrs, i could not change her opinion, or her ways of trying to make me believe the lies she said so that i didnt see what she hated about herself.
it didnt work for me, and i know that these types of people need alot of work and i dont believe u need to bother.
i hope u get a better idea of how u would like to move forward with this.
well wishes
self