So, my dad has bipolar disorder and has been a functional alcoholic his whole life. He is a wonderful father, but was a terrible husband to my mom, mostly due to his bipolar issues, and what I now believe to be undiagnosed autism. He had a successful career and was a good provider, but it has been a hard road for my mom. He is 72 now, and my mom is STILL dealing with his issues because she divorced him once, but came back to him when she realized she needed his financial support. It's not a good situation and one I would never want for myself. In my experience (my dad was diagnosed with bipolar when I was around 4), bipolar is very similar to alcoholism in that treatment is only successful if the person is dedicated to it. Unfortunately, the bipolar meddles with the person's perception of reality and they feel invincible often so they think they are cured and stop taking meds, which causes these crazy cycles of mania and depression to worsen. Adding alcohol to the mix makes it even worse. My dad, for his part, never abused alcohol to the point where he was a danger to anyone, but he has continued to drink steadily his whole life, against the recommendation of his doctors.
I'm no psychiatrist, but this sounds like a very serious case of alcohol medicated depresssion/bipolar disorder. His inability to recognize the problem is likely due to a mental health disorder that is not allowing him to perceive things as they really are, and for that, it's not really his fault. HOWEVER, the lying, sneaking and trying to cover up the drinking are CLEAR signs of alcoholism, and even in the absence of a mental health condition, should be enough for you (OP) to put your foot down and demand change, or else you should leave. Loving someone is not enough to fix them. They have to want that for themselves and for the relationships in their life.
My husband has been battling depression for about 10 years now. He refused to get help. He self medicated. He remained high functioning, as a military officer. He was able to control his drinking and be responsible, but he tried to numb the pain with alcohol. I begged him to see a doctor, many times. Last fall, he began to seriously contemplate suicide, and one night while driving home at 80mph on the freeway, had to fight the urge to swerve the car into the center divider. He made an appointment to see a psychiatrist the next day. He told me nothing of this, but let me know 3 MONTHS later. All I knew is that he had finally seen a doctor and gotten a diagnosis and meds for depression. I had NO idea it had gotten to that point. I cried so hard when he told me that. I would have been devastated if he had gone through with his plan. His treatment so far has turned his life around, but it is still a struggle. Our marriage experienced a sort of revival when he "came back" to me as the man I fell in love with all those years ago. There is hope, but it won't come easy, and again, your husband has to first recognize the problem and then work to get better. It won't just happen, but if he values your marriage and wants to be an active parent to your baby, he will make the effort.
You need to talk with him. No more excuses.