I’m so stuck

My bd is so toxic. He’s not a good bf to me at all and I’m not happy. But I feel stuck with him. He’s a good dad and provides for our son so I feel there is no way I can get full custody of our son. If we break up that means he’s going to move back home 4 hrs away from me, which also means I’d have to leave my son with him prob weeks at a time and I don’t trust him to be up there w/o me at all. I don’t trust my bds mom to keep my son safe and I know for a fact my bd will leave him with his mom. So depressed. Idk what to do.