I think my husband is hiding something from me... what would you do?

So, the other day my husband came home from work in a weird mood. He is active duty in the Air Force. He was very quiet and distant from me and the kids when normally he is very warm and playful. This isn’t like him. I of course asked numerous times if everything was okay, and he said “yeah, I’m fine” but again, he said it so... detached. Like he wasn’t all there. He was very distracted. I know something is bothering him or is wrong. And I figure it must be big. But he will not tell me what’s wrong. But I’m starting to get angry at him for acting like this around me and the kids. He just sits there and doesn’t interact with anyone. Won’t talk to me. Snaps at the kids. But every time I tell him to open to me, he just absolutely denies that anything is wrong.

Deployment? No, can’t be that. We already know he’s deploying next year.

Money? No. Bank account is steady.

So what is left...?

Cheating?