It can be hard for me based on things he says to me as to what is my fault versus what is his fault. When I’m repeatedly told nothing is wrong and it’s all in my head because there’s something wrong with me - then I doubt myself a lot. Then I worry if I’m the problem that no relationship with anyone will work because I’m warped (his words).
Look, the simple fact is that you and he are seriously at odds with how you see the world/reality.
You think he's often apathetic, nasty, gaslighty, callous and critical. He thinks you're demanding and oversensitive and his shortcomings are all in your head.
And either of you could be right! Maybe it's you and maybe its him. None of us here on MN know you or him, and none of us witnessed the myriad situations that led up to you coming here to talk about this. From what you say, it sounds like you've got a closer grip on reality than he does, but of course, that's because you've posted from your own perspective. His perspective might seem equally convincing if he posted from it.
The important thing is not 'who's right and who's wrong', it's that there is no overlap between your perspectives. There's no comfortable place of agreement that will allow you to move forward happily together in your relationship when there's such a gap between your perspectives and he's unwilling to treat your experience and feelings as legitimate or work towards a resolution.
You could decide that he's 'right' and you're the problem, and stay in the relationship trying harder to ignore your actual feelings just like he does, and attempting to figure out how to 'be' so that he will become less critical, less nasty and less apathetic towards you. Maybe go to the gym/get a boob job? Offer more sex? Never complain again?
Is that going to result in you being happy? I doubt it. Or you could stop looking for him to validate YOUR ACTUAL EXPERIENCE AND FEELINGS and validate them for yourself.
The way you do that is to say to yourself:
"I feel criticised, and ignored, and spoken down to, and treated like an option by the person who has the privilege of taking up the space in my life reserved for a romantic partner. The way he treats me makes me unhappy. And he doesn't care about how I feel, and thinks I'm wrong to feel this way. So I know he's not going to change. But my feelings are valid TO ME and they're telling me I'm worth more than the treatment I'm getting. So I'm going to act like I believe in myself instead of him, and stop giving space in my life to someone who mostly makes me feel miserable and doubtful about myself."