I seriously doubt he's suddenly fallen "out of love" with you. But trying to stay sober is incredibly difficult and a huge internal upheaval under the best of circumstances--and the way he's doing it--white knuckling--is hardly the best of circumstances.
If I had to predict what will PROBABLY happen--there's a better than even chance he's not done drinking. I'm not predicting he CAN'T recover, only that I'd be quite surprised if this was his last drink, with no support. I know many people who have recovered without AA or a formal "program" but they are usually getting support of some kind--from a therapist or a group like SR, and they are usually doing some of the same kind of internal work on themselves that the Step work accomplishes.
Want to know what's probably going through his head right now? "Maybe it wasn't so bad, it's just beer, I'll never be able to have fun with my friends again, this is all an overreaction, yada yada."
If someone told you that you had a medical condition that would be potentially crippling or fatal if you drank, you'd probably have not that much difficulty giving it up for good. For an alcoholic, the prospect of never drinking again is overwhelming--the end of life as he knows it. The other aspect of alcoholism--aside from not having that "off" button--is an obsession to drink. That's what's working on him now--the obsession.
AA talks about the "spiritual awakening" as being the only thing that will relieve the obsession. That doesn't mean a religious conversion, or visions or anything--it's defined as a "personality change sufficient to bring about recovery from alcoholism." The Steps are one way to make that happen; there are others. But all require a lot of work and introspection.
Very few alcoholics stay sober on their first attempt. Most of them start out the same way your guy did. And, realistically, most people DO have to try--and fail--on their own, repeatedly, before they realize it's too big for them to handle completely on their own, by using sheer willpower.
So I think he's far from hopeless--he at least has admitted alcohol is causing serious problems in his life. Lots of people never even get that far.
My suggestion is that you work as hard as you can on your own recovery, and taking care of yourself and your baby. As I said, I think there's a good chance you're in for a bit more drinking before he is ready to do what he needs to do for this to "stick."