
You’re not stupid at all. It can be very difficult to leave someone especially when you love them, but at some point you have to question how much do you love yourself. If you love this person more than you then sure, stay, and suffer for this person. But if you love yourself more, and you should, then you deserve to be treated as such.
When it comes to strength, if you feel like you don’t have it in yourself then trust in a power greater than yourself. If you believe in god, use Them. If you have a therapist or a trusted friend/family member , make a plan with them and trust that. It can be scary and tough but in order to get through you have to go through. You can do it
You ain’t stupid; you’re learning. Everyone falls in love with at least one asshole. You can’t change him, but you can recognize that you deserve better. It will hurt for a bit, but once you’re away, you will have the space to learn to love yourself. Then you’ll never have to go through this bs again.