Maybe you can try talking to him about it? My hubby tends to flare up easily when he does not get enough sleep. There was once when we were on a holiday and he kept getting angry with the kids over super trivial things like spilling of water bottle etc. It was all because he did not manage to get much sleep on the flight the day before. I flared up too and thrashed it out with him. He was stumped but things got better after. Sometimes they do not realized how their behavior is affecting us if we do not tell them in the face.