I’m not a frequent poster but I have some experience here. I went through this early in my relationship up until after my first DD was born. She’s ten now.
It was really tough and our relationship has not been easy, but we did get through. I don’t want to defend your partner at all, he’s an utter twat and deserves to be dumped.
I stuck it out through love, fear, low self esteem and feeling trapped.
Over the years I’ve improved my self worth, built confidence and built the belief that I can go it alone. Over time my partner matured, dealt with his own insecurity and realised that I was ready to go it alone if he didn’t step up.
And we’re here, still together and pretty happy (with the help of an amazing therapist). We’ve rebuilt trust and gained respect for each other. It’s by no means the fairytale.
I’d recommend doing a deep dive into what’s behind his behaviour, while getting your ducks in a row and keeping one eye on the door.
It doesn’t sound like its practical to walk away right now, but you could focus on yourself, improve your self esteem and be as selfish as you like until you get yourself ready to go. It’s possible he will see what’s happening and also do some work on himself.