Many men like to pretend to their family and new wives that the ex was psycho and won’t allow him to see the kids, to save face. An excuse as old as the hills. Often, when they do take the ex to court, it’s at the insistence of parents or a new wife who they want to look good for.
Abandoning the kids of a previous marriage because he can’t/won’t do more due to the new batch of kids is not uncommon either.
I doubt it’s the case (maybe jog works out like that when you’re there because you’re critical and she wants to be out of the way when you’re there), but if it is, what is so wrong about taking care of his own kids and home???
Ask yourself, would you have a problem if he spent that time out doing a sport?
Please stop the sexism. Often it’s the older generation of women perpetuating misogyny, it’s so ugly, not to mention ignorant in that you’re shooting your own self in the foot, stop it!
You’re well on your way to becoming excluded by this family and I wouldn’t blame them.
Not your house, not your kids, stay out of it.