Loveactually,
You are acting as his enabler and you cannot enable him any longer. Its for his sake as much as yours - you are protecting him from the consequences of his actions.
Who buys the alcohol?. Please tell me you're not buying it for him. I only ask this as he is not working and you are.
"I want to think he will change" - well you can think it but that very thought will cost you dearly. Making him go to AA was actually a mistake on your part. He has to want to solve his alcohol dependency problem for his own self; you cannot make him go to AA for you. Only going because someone else has told you to is doomed to failure. That is also likely why he stopped going. Denial also plays a part here; he likely underestimates the amount he drinks and the effects its having on him and also you as a couple.
He does not want to leave because he has it made with you bankrolling him and his alcoholism. You're enabling him currently so he has no real incentive to leave.
Seeking legal advice from a Solicitor or contacting the CAB is one option; if you own the property and he is only your partner his right to stay in your house is in question anyway.
His primary relationship at present is with drink. You and his unborn child are well down his list of priorities. He will drag you both down with him ultimately; you have to act now to save you and your unborn from any further misery.
You need to primarily concentrate on your own self and that of your unborn child now and plan accordingly.
I think that things will particularly get a lot worse for you when your child is here. It sounds also like he has an addictive personality and has swapped one addictive type behaviour for yet another - alcoholism.
Love is not enough in these circumstances and love can also turn swiftly to hate.
I would suggest you contact AL-ANON as they can help family members of problem drinkers. You need to lovingly detach yourself; enabling him is not an option.
I will put up Al-anon's details for you. I would urge you to call them asap.