I'm sorry your going through this...if your willing to stay he NEEDS anger management....physical abuse actually comes out more in a man when their wife is pregnant..and I fear that this is only the beginning...he needs to be able to control himself and some can and some cant....this is defenitely a red flag though and for the fact that your relationship is a constant roller coster I would suggest a break...you dont need this especially while you are prego. Dont defend his actions because they are WRONG.... he will apoligize over and over and tell you he would never "push you around again...but isnt this the second occurance?? Think about the safety of your baby and yourself....is he controlling? Jealous? Quick tempered? Insecure? These are warning signsWhat does your family think of him? Because believe it or not your family has the best judgement because they can see from the outside and the inside.......whatever decision you make...be careful and good luck!
I don't think it would do any good to tell you to leave him Emy725 as you'll probably do what most women in your position would, you'll make excuses for him and stay. Then one day he'll physically hurt you so bad that you might actually leave him then spend a good portion of your life questioning yourself as to why you stayed in the first place. If I thought you would listen, then I would say leave him now as the chances are very good that it's going to get worse. Don't get me wrong but you woman have a way of turning the meekest men to madness, but no matter how a woman treats or what they do to a man, theres no excuse for him laying hands on her. He has the option of walking away. So do you.
If this was a 1 time isolated incident... where he pushed you. Then, I would say give him a benefit of a doubt, go back with him and work on the relationship. But, you said that he had "... done this once before." So, I would now see the pushing thing as a potential pattern as to how he handles anger and stress. Just be aware that pushing usually leads to shoving which often leads to hitting... etc. And, if he starts treating you that way, who's next? the baby?
I'm sorry for the situation that you're in... still working on the relation but with a baby on the way... I suggest counselling for both of you. Find out why he gets mad like that and reacts like that. Even if it's only the second time, unfortunately it is the beginning of a pattern (been there, done that... so trust me). I know you love him and believe he loves you, too, but I've learnt that it takes more than love to make a relationship work out. If you can, stay at your parents' for a bit and see if he does make changes. Also, keep in mind that while you are the one physically pregnant, he is also pregnant (in a way) and he is going through stuff, too. Having a child is a BIG change in anyone's life, no matter how old you are. Keep posting and let us know how things work out. We're here to help!