The way you're being treated is not OK. You don't deserve it & you can do better... if you can, get out of there. He's only making your mental health worse, with the way he's treating you. I've stuck out a toxic relationship for far too long in the past too, & the after-effects of the gas-lighting & abuse I was subjected to continue to affect me to this day, a decade or so on.

Your mental ill health isn't a personal failing, it's primarily a skills deficit - that's what BPD is. Your doctor continuing to give you various meds probably isn't helping either - meds aren't meant to be the primary treatment for BPD. Psychosocial therapies & supports are far more effective, according to evidence. I tried 6 different types of antidepressants over almost a decade, & none of them were as effective as the Dialectical Behaviour Therapy (DBT) I've done since. If you can, I'd suggest changing doctors, & try to get some form of evidence-based psychological treatment which has been proven to help people with BPD, or even a support group, perhaps... you've reached out here, so that's a good start. There's heaps of stuff online ATM due to COVID, so maybe you can find something virtual that's easy to access.

Look, living with BPD is hard. It's hard enough dealing with just that, let alone when you have untreated (or ineffectively-treated) BPD, & you're in an abusive relationship... do what you can to make things easier for yourself. You don't deserve to suffer, & things can & will get better. Look for ways in which you can move towards the positive, & away from the negative, impacts in your life. And keep reaching out for support! It's scary initially, but it gets easier, & a sense of community is like balm for the soul. All the best...