Yeah, he was a setup for a midlife crisis: retiring from being an athlete ( without the fame and fortune he probably sought, I'm guessing?) AND his father dying. That's a setup for feeling like life is passing you by and you better go do what you want before you're dead.
Your guess about an OW not wanting him to go on a trip with you may be a good one.
What is he doing for work now that he's out of sports? How will he pay child support? Are there any jointly owned assets or debts?