Hi OP. Even before reading other posts I thought 'trauma bonding'.
You are NOT warped, he is. They suck you in with a cack-handed charm offensive and it can be very persuasive, they criticise you to make you want to please them, to do better, and people like this are very good at ignoring your boundaries and making you think you are at fault for having boundaries at all, they take your peace of mind and make you doubt your own sanity. Meanwhile you are left believing you love them (when the butterflies are more to do with anxiety than affection) but constantly wondering what you are doing wrong, when the answer is nothing.
Manipulators do not like being rejected, they have to be the ones who reject others, their fragile ego can't cope otherwise. You left and that is still needling him 2 years later. he is trying to hoover you back in so he can treat you badly all over again and regain his sense of superiority. It's been irritating him since you left, not because he cares about you in the slightest but because it doesn't fit the narrative he's built around the relationship.
If that's not enough, he doesn't want your son around, why would you choose anyone over your own child? He even told you he doesn't love you, take that as true, people like this don't love.
And if that's not enough, he should be gone just for calling you a cunt. I've been with my partner for decades and if he ever called me that, or even bitch, just once, he'd be gone. This guy you were with for just 18 months and he did it multiple times. You binned him, leave him in the bin where he belongs.
He can probably be very charming and appear wonderful to others because they only see the superficial mask, or they see past it and walk away. But he is coercing you. He has even told you that you have to put the work in to regain his affection, how big of him.
Block contact, ignore any of his messages in future and have zero to do with him. Don't bother even to tell him you're doing it, don't give him any more of your valuable time at all, just congratulate yourself that you are free of this bell end and get on enjoying living the life you've made for yourself.