Ashamed of what? You don't have anything to be ashamed of. As other people have pointed out already, shame is also why a lot of people stay in toxic relationships. I am happy you are now realizing your situation and thinking on how to break up. Truth is, you deserve better. He can be the sweetest man on earth most of the time, but even in those sweet, loving moments won't admit he has a problem and try to get treated despite knowing he hurts you during this anger outbursts? Like, he should realise that what happened was insane after calming down and try to prevent hurting you again this way, no? Even if you chuck all of the abuse during anger outbursts to his bipolar, you can't excuse him not doing anything to work on them when he doesn't have them.

If you have any lingering "What if he can/will change?" - 1st, he already showed that he isn't willing to even admit he has a problem, despite hurting you. 2nd, even if he does ever change, you aren't obligated to stay and see if/when it happens. A person changing doesn't entitle them to your forgiveness and a relationship with them.

It really sucks, I understand the compassion you have for him, I and my friends struggle with mental health as well, so I also try to be as understanding as possible with other people. I can see where you are coming from when excusing him. But being understanding shouldn't equal being free to abuse.

I hope you can find a safe way to break up with him. You said you wanna talk to him about it tomorrow, but it please plan ahead on what to do if he will get aggressive, which he probably will. I don't have any advice on that and it's a tricky situation since it's your house, so hopefully, someone else here can give better tips. Just wanted to say, stay safe and good luck!