I'd bet his ex accused him of being a narcissist so now he throws the term around.
Never accuse a narcissist of being one. It's like telling a lion 'hey you're a lion! And you're chewing on my leg!'. Pointless.
Plus, he'll reverse it on you.
Don't waste time confronting him on anything. Just tell him it's over because you don't want to be with him anymore. No need to give reasons. The more reasons you give, the more ammo he has to turn round on you.
Just 'John, this isn't working for me anymore. I'd like you to leave'. If you have to give a reason 'I don't love you anymore' is a good shout. Because there is no answer if he asks 'why?' to that, that he can use to argue back. It just 'is what it is. I don't love you anymore. Pack your things and leave'. Ideally, do this with some suportive friends or family present.
He will be spiteful, he will call you cold or nasty or any other similar thing, claim you never loved him, tell you he thinks you're cheating etc... but at least he cannot talk you into another chance. Just 'OK John but we're still over'. Don't waste breath arguing back.
Don't let him convince you he has nowhere else to go. That's his problem.
Ideally ( especially if you think you'll have trouble getting him to leave) I'd wait till he was at work, have the locks changed, then text dump him. He isn't owed face to face. Abusers are not owed that. 'No. Because I don't want to' is a full sentence. Drop his stuff round his family home or his exs if they still talk. Anything else can be posted to him recorded delivery.