“He recently said to me ‘not once in over 3 years have I said I want to break up.’”
Read that back carefully. He’s never SAID it. He might have thought it but if he’s got sex on tap and a woman bending over backwards to appease him and stroke his ego, no matter what he (metaphorically) throws at her, he’ll stick around and see how far he can push that.
“He will just say he is who he is and if I don’t like it then that’s my problem.”
To be fair, he does have a point there. Why SHOULD he change who he is? Why should ANYONE change to become the person someone else wants them to be? He’s basically telling you that his core personality is shit and he’s happy about that and you can like it or lump it.
“Hasn’t said that about his ex but did say she always thought she was right and she did him a favour by leaving”
Interesting. So she left him did she? That’s as close as you’re ever going to get to him admitting he was the problem.
“This is the first time I find myself feeling so confused and insecure, constantly questioning and honestly it’s like I’m losing my mind.”
Putting him aside for a minute – do you think feeling like this is a healthy way to feel in a relationship?
“If I’m not important enough to make an effort - why wouldn’t he just end it with me? This also baffles me”
Because he’s enjoying the sex on tap and the ego boost of a woman bending over backwards to become the person she thinks he wants whilst trying to change him into the man she wants. Once he’s bored of that, he’ll end it.
Or you can decide he doesn’t get to tell you how you’re supposed to feel or react to his shittyness and, instead of trying to reason with him or call him out on it, just call time on the relationship. Don’t spend eternity wondering how you can encourage him to be nicer to you – he’s already as much as told you he doesn’t give a shit about how you feel.
TLDR; no you’re not an insecure pain in the arse – he is. Trust your instincts here. You’re feeling insecure and unsettled because you’re finally seeing his true colours and you don’t like them. Don’t try to change him, or yourself. Just leave him.