Yay! First non-liason to respond

Anyway, there is definitely something going on, but it may not be an affair. You've been together for 17 years so he might be starting to have hormone related problems that are upsetting him and creating performance anxiety and moodiness, might be stress from work from all the traveling, could be any number of things.

I agree that you guys need to have a conversation about what's going on and a couples counselor could help as well.