Thats awful...i am sprry hang in there
Gosh, I'm very very sorry to hear this. He isn't apologetic or contrite or anything? That is a very bad sign. I hate to say this because you are having a baby and this can be hard to do but if you just let it slide. . . what is his motivation to NOT do it again. I think you have to leave him hon or he will be a chronic cheater. He's not full of remorse trying to make it up to you . . . you found out and he's like "oh well". What can you do with that?
Do you have parents you can go stay with and a job and stuff??