It sounds as if both you and your hubby/boyfriend need to do some growing up. Well A lot of growing up. First off it is very immature of you to get upset at him for still going to his stag party, even if you decided not to go to the cenima, thats your issue not his, just because you didnt want to go out, why spoil his fun?
Second, It was highly irresponsible of you to make the decision on drinking while pregnant, just because your man went out and had a good time.