I would look at it as his taking the opportunity to spend more time with the kids. It sounds like your H is taking a more active role with the kids. So, I would look at it as a kid thing and let it go.
You are trying to mind read. Please, don't. It will make you so crazy. You don't/can't know what he's thinking. When he says or clearly does something that shows you an opening, then it's up to you how to handle it.
Bottom line, you know him, I don't.
I will tell you that my H has (when I have asked) been there to watch D's. I have also allowed him visits in my home (out house) to be with them. Has it meant anything with regards to me? No.
Am I insane? Uh, that would be a yes.
HUGS
It sounds like your H is taking a more active role with the kids. So, I would look at it as a kid thing and let it go.
