What a horrible person he is to treat you that way, and also encourage his friends to do so.
LOVE doesn't behave that way, and you and your little baby most certainly deserve better. No one should be subjected to that disgusting behaviour. He does not deserve you or the baby.
If you stay in this situation, he will make both your lifes an absolute misery. Get yourself out as soon as you can. Don't even tell him you're leaving! Arrange it for when he's out of the house and just go. He doesn't deserve the dog either, so take it with you. Especially if he's cruel to it.
This really isn't something you can " fix". He is not, nor is he remotely likely to be, the man you would like for a partner and loving father.
Your mental and physical health will certainly be impacted by all this stress. Remove yourself from it as fast as you can. On your own, you can have peace, and look forward to your little son coming into the world. I really feel for you, and wish you the best.
Much Love
Bute xx