I'm sorry, but this sounds exactly like my brother just before he was diagnosed with late-onset BD.

Pretty normal, stable, everything seemed fine and suddenly exhibited this really strange, manic episode - with a very big event similar to your husband's. It was easy to write off initially but his behavior really sealed it. He tried to normalize it - like "Yeah, this is fine, maybe a little out there but still how an adult behaves! No harm done."

At first, it was easy to believe, he was in such good spirits and life seemed on the up and up when you talked to him - although the behavior was odd. But then later you'd find yourself thinking, "Never in a million years would I do this. So why is it normal for you to do it? And so suddenly and out of the blue too."

Imagine if something had happened to your husband on the flight over or while he was there. You never would have known. This isn't normal, responsible, sane behavior. When you have a wife and kids, you don't just ditch them for a 4 days around the world tour to TAKE A SELFIE. That is not the behavior of a person with a full grasp of their mental faculties.