As I say, not all gifts are wrapped in pretty packages and tied with a bow, some appear as Sh!t Sandwiches.
Now that you've reached a new level of letting go, how about having a talk with H? No shame, no blame, just the facts about how much you're willing to foster his R with his children.
Your boundaries.
Then let it go. He is an adult, he can do this if he chooses to.
A note about resentment, my bugaboo. Don't invite it in. If you're doing anything for any reason other than it's what you want to do or believe to be, in light of your values, the best thing to do, stop doing it. Make choices that are yours because doing anything less than that is fertile ground for resentment to grow. Knowing your boundaries, stating your boundaries and maintaining your boundaries is key. People can't respect our boundaries is they don't know them.
Many of us fear setting boundaries because 1) we want to be liked and 2) we might have to defend the boundary. My answer to that: 1) it's better to like/respect yourself 2) it's better to be surrounded by people who respect your boundaries. Let those who don't fall away.
I hope you don't picture Yoda in your mind when you think of me but I leave you with this: “Fear is the path to the dark side. Fear leads to anger. Anger leads to hate. Hate leads to suffering.” <(-.-)>
Me 57/H 58 M36 S 2.5yrs R 12/13
Let me give up the need to know why things happen as they do. I will never know and constant wondering is constant suffering. Caroline Myss