Fed Up, Feeling Like Bending Over Backwards Trying To Feel Better

I am in this toxic relationship that has been going on way too long. I feel like my life isn't fulfilled and is always in turbulence.

I have a job that I like and a hobby that keeps me sane. I am holding a temporary resident visa and relying on my partner for this. He manages to annoy and push my buttons every day. He would call me names, nag, be confrontational, disrespect me, and talk about how much he'd like to have sex with other girls - coupled with his neverending mood swings.

I feel like walking on eggshells. I feel frustrated to the point where I'd have breakdowns. Instead of listening to / helping me out, he would call me crazy, tell me to move out, and threaten to cancel my visa.

The problem is, I would spiral and be unable to pull myself out of these breakdowns. I won't let myself stop. I would yell at him, followed by crying and feeling like an absolute mess. Like I despise myself completely. I have a massive guilt every time this happens and sometimes I can't go about my days....

If he is so horrible, why can't I LEAVE? why am I so scared?? Why am I screaming instead of leaving?? I know the visa thing really bums me but surely there are better options out there. I can't keep going like this as I feel like it's hindering my career.

I just want some peace... but it seems like I am not letting myself have one.