I understand-- you feel your h may be heading this way, as it sure doesn't sound like he's acting like a committed husband at this point; hardly even an on again/off again bf. I'm going to try to maybe open up a few "ideas" you may not have considered...that may or may not have any basis of truth for you...just brainstorming, so please do not be offended by anything I say.
My h was in the mil too (af)--we had a few tdy's, though nothing as long as a year. He had a school to go to for 6months that he wouldnt let me go with him to. It was 5 hours away as well. So, yes, I do have a sense of what you're going through.
He certianly has some issues..but maybe a part of it is that he was away for a long time. Things happen when people are seperated from their spouses esp when by hundreds of miles that don't happen when the spouses are together. They look for ways to fill their lonlieness and to find fun in a new, strange place. As such, they change. They find new things they like and get into a certian new routine they are comfortable with. That goes for both of you--I am sure you started doing new things or hanging around new people...and at the very least assumed new responsibilities when you h left. My thoughts are that prehaps he has grown "used to" being alone again. He dosen't feel he knows you anymore, and maybe he's not sure (or uncomfortable with)how to jump back into his family.
I had a lot of resentment towards my h when he came back home (b/c he wouldn't let me go)-and I wanted to be away from him..opting to go out alone and locking the door when I took showers or used the restroom (as opposed to normal open doors)-- granted, I was resentful b/c he wouldnt let me go with him..but maybe your h is resentful that you were home all this time, enjoying the benefits of his service in your house with your family--and all the lovely amenities of home and community...while he was in a nasty war zone, where he didn't want to be, missing simple pleasures of life. Maybe that's a small part of his weird behaivor.
As for what you do..I guess plan a. Work on you, make sure you do not lb, keep the house spotless, and try to make your home as inviting and plesant as possible. Maybe even inconspicuously set up some nice framed pics of you and him from dating years and the 3 of you as a family, if you have them. --not obvious places...but maybe where he can see them. And keep your baby looking her best..just all the things that would make it very, very hard for him to leave. Good luck, I hope he comes out of this funk soon.