TBH, you BOTH sound somewhat overwhelmed.
Let's give everyone the maximum allowance of Benefit of the Doubt here and break it down.
So there was a lot of work on at your home, major works that meant you had to move out. Then the birth, then the complications, and all the while he has his own projects. You say you were teary too, and emotional, which of course is to be expected, especially if the baby has to go back to the hospital.
TBH it does sound as if he's struggling to handle it all. I don't particularly agree that he's having an affair, I do get the sense though that he is running away from it all.
OP, you say you are self sufficient and independent and were used to his 'fluid' work routine, but that you feel that he ought to check in more. You also say you used to work, but are SAHM now.
FWIW, this H of yours is going about this all the wrong ways, and actually CAUSING you to panic when it'd be so much easier to say, Love, got a mad job on, dunno when I'll be back. Or Got a 4-day trip, won't be able to talk to you while I'm away, but text me if you have any problems.
Blokes seldom do the logical, opting for the bury our heads in the sand choice, which will always send us over the edge. Now that your life has changed beyond measure, you are doubtless nervous and feeling a little out of your comfort zone, but don't have the option of going M.I.A. He doens't have that right either and he is being wholly unreasonable.
I think the best way, initially, to attack this is to sit him down and gently point out that you are freaked out too, that you are scared, not sure of what's what with the world, but that having him near, or chatting things through with him really help you to make sense of things. Ask him if there's anything he'd like to talk to you about.
You know you have a right to have him more involved in your life, your parenting and your family, but there are ways of negotiating it. This guy's not equipped to handle it at the moment. AW Diddums is absolutely right, but saying it won't actually help the situation. Yet.
Change your tack with him, back off, be supportive, but clearly communicate that you would like to know where he is, and how he is, and a rough idea of when and if he'll come back. Be consistent, but remember you are not his keeper. You are not his mother. He is big enough and old enough to communicate details with you and be where he said he will be when he promised, or to tell you I'm running late.