Is emotional abuse grounds to get full custody?

My fiancé is such an angry and miserable person. He starts fights with me every single day, and is trying to force me to give up our rental and move back in with his parents because “doesn’t like wasting his money on rent”

His mom is an awful woman to me, treats me like I’m the worst mom in the world (actually told me I’m a horrible mother before because I didn’t let her babysit one time) and I don’t want to live there.

Now he’s saying if I don’t come with him to live there he’s leaving me, but I’m so terrified if we split up and he gets part custody that my sweet happy baby would wind up hurt or neglected.

As of now he doesn’t do anything with him but yell at him and push him if he’s in his way. (Our son is one) So i don’t want them to ever be alone. I want to leave him because I’m so unhappy and done being treated like this. But I don’t want to chance him ever being alone with my sweet baby.

Is his emotional abuse towards me, and anger towards our son grounds for me having sole custody? If it’s not I’m just gonna keep taking it because I’m so scared of him snapping and hurting my baby.

But I really don’t want my son to be exposed to this constant anger and ridicule anymore.

I live in Oregon, I don’t know how different states custody laws are.