I agree. Remember that nobody can/should manipulate you into a relationship that is not right FOR YOU. You have free choice here. I understand Life happens. I'm sure he was not expecting to find himself feeling this way about this other person. But HELLO??? He needed to communicate! Not let things get to the point where he is wanting to share households without having a LOT of communication with you about how he is feeling and how YOU FEEL!
A big flag here is that you are afraid to bring anything up because he gets angry. You are responsible for communicating your needs, he is responsible for his reactions to that communication. Sounds like he is avoiding accountability on many levels which tells me this is not someone who has the emotional maturity to be a partner to ONE...let alone TWO!
Integrity is never something I want to have to negotiate for with someone. It is either there or it isn't. He is lacking in that department...do you truly feel he could earn your trust again?
HUGS to you and hang in there. Take care of YOU here.