My stepson, Leif, and his Swedish wife, Cilla, are about to go to Guatemala, where they will meet the baby whom they have begun the process of adopting. He was a strong presence during Christmas, this boy none of us have met yet who already has become part of our family.

One of my sons turned to my mother as Cilla unwrapped a baby quilt and said, 'This makes you sort of a great-grandmother.' My mother looked blank for a moment, until she put it together: This baby from Guatemala will be the nonbiological child of Leif, to whom she is not biologically related. But Leif is the half-brother of her grandchildren, so that does make her sort of a great-grandmother.

By marrying and having children, my husband Eric and I constellated the family that links Cilla and her new son to my mother. We created a family of boys that allows basketball in the kitchen and pets on the furniture, a family that says a blessing at meals but usually at some random moment in the middle-a family, like all others, that has its own idiosyncratic ways of doing things, its own humor, and its own undercurrents.

There is a big undercurrent in our family right now because Eric's and my marriage is dissolving. I use that word rather than the other D word, which implies a meat cleaver through the center of the family we both love so dearly and a death knell for any enduring friendship between us. Our marriage has been dissolving bit by bit for a long time: cracks, fissures, battering by the elements, tectonic shifts. But our family has held strong-and continues to-through all the vicissitudes of our relationship. For the foreseeable future, Eric and I are living under the same roof. With fewer kids at home, our house can accommodate both of us, as well as the space between us, at least for now. I have been imagining this process of separation as analogous to weaning our kids-so gradual that one stage seamlessly evolves into the next.

Someone asked Margaret Mead how she felt about having failed marriages. She replied that she didn't have failed marriages; she had remarkable partnerships that were appropriate for different stages of her life. I like that way of holding it-by any measure, Eric and I have shared a remarkable partnership. And the way we end our formal partnership should honor that accomplishment as well as lay the foundation for the future of our family.