Q. My husband and I each have children from previous marriages and now have twin toddlers of our own. My daughter, age 10, lives with us but also spends time with her dad, while my bonus son, Billy, 11, lives with his mother in another state. Our toddlers adore their older siblings. How do I explain to the little ones where their half-brother and half-sister are when they aren't with us?

A. The best approach is honesty. Even if they don't understand what you're saying yet, as they grow up they'll eventually understand the concept, which is simply that both you and their Daddy were married before you were married to each other. And, the explanation would go something like this: "Daddy was married before Mommy and they had your brother, Billy. He lives with his mommy (wherever she lives), but we love him, too, and he comes to see us (explain when you will see him next).

Take lots of pictures when the older kids visit, and when they leave, make sure the pictures are around the house so the toddlers can see them and grow up thinking of their half-siblings as part of their family. Send the older kids pictures of when they are with you as well so that they can see them all year round. Make sure you or your husband talk to the kids' other parent first — explain how you are attempting to normalize relations with the younger kids, and ask if he or she will support you by sending pictures of their family so that the little ones can see where their brother and sister are when they are not together. Plus, those pictures can serve as keepsakes to prevent homesickness when the older kids visit you.

In this day of back and forth, the most healthy way to approach shared custody is to openly cooperate with your child's other parent. That means no badmouthing of the other home, and no "You know you like it better here" remarks

Probably the most damaging and misused phrase in the world of co-parenting is, "When you get to be 13 you can choose which parent you want to live with." That's not written in stone in any state and can compromise a child's ability to trust either parent if the child has been primed to believe it, reaches that age, and then finds that it's not necessarily true.