First thoughts, will try to remember to come back.

1. You should look up Al-Anon in your city for some added support, or find a therapist so you have someone to talk to.

(This is if you plan on staying with this person)

2. Leave him. He sounds like he could become potentially dangerous (and already is dangerous, even if it's only sporadically) and that is not a healthy environment for you and DEFINITELY not for your baby on the way! Speaking as a person who gave up drinking and who knows what alcohol can do to a person (as the child of an alcoholic) ... people don't change unless they choose to do so, and he doesn't sound like he's choosing to do anything constructive to help himself out. So leaving him might be the wake up call he needs that his behaviour affects others. It doesn't need to be permanent, but long enough that he cools down and gets professional help. It's not manipulative to do so, it's healthy. Staying in a relationship in a home where you could get hurt is NOT healthy.

It does not matter that this is a "once in a while" type of an incident, especially when a child is in the picture... it is very, very DANGEROUS. As well, one doesn't need to have a physical dependency on alcohol (or any substance) to have a psychological dependency on alcohol (or any other substance). That means if he CHOOSES to quit drinking and stays sober - basically forever until he figures out his anger issues (at the very least until then, but sobriety completely forever is also an option) - then he'll be better off for it.

From his past history with alcohol, it does ring very big warning bells for a problem with alcoholism.

PLEASE keep yourself safe.