Feeling angry with SO

Lately since finding out we are pregnant, I've been having a lot of tension inside for my SO. He has lied to me in the past and also cheated on me with his ex. Since then I haven't been able to trust him. Now everything he does really irritates me because I feel like he's not trying to earn my trust back. I told him today I'm done with him. I can't take the potential of him hurting me again. Without effort towards being trusted again I can't be with him. However we live together and I'm 7 weeks pregnant with my first child. He has 2 from a past relationship. So my question is am I just being hormonal or is this a good cause to break up with him? If we don't have trust, we don't have anything.