The boys are 13, 10, and 5.
The 13yo has been through so much with her, he is jaded, and just does as she asks to not get in trouble. He still calls my dh "Dad", and knows he has a home with us when he needs it.
The 10yo is all confused. A year ago he told my friend's ds tha he had 6 moms, four of them were male.

The 5yo is too young. He doesn't know yet. I do admit I've had the whole conversation: "you have a mom, and a dad, and a stepmom, and a stepdad! isn't that fun? Now, who is who?" with him once.
I started joking with the oldest that I was the Wicked Stepmother (wicked, the way Ron says it in Harry Potter), and that turned into the little cuddling up to me saying "you are my Very Nice Stepmother, and I am your baby!"

It's our game now.