02/26/2013 12:42 pm ET Updated Apr 28, 2013

Bra Shopping In A Blended Family

"Mom, Sophia wants to take me out this afternoon."

"Ok, but I thought we were going to go shopping."

"Well, she wants to show me our new apartment. She says there's four pools."

I've got custody of my daughter most of the week, so, if her step-Mom wants to take her out for a few hours on my weekend, that's great. I'm no daughter hog.

The rest of the morning went by in typical fashion, me nagging said daughter to work on her homework, said daughter assuring me she was, but clicking the TV or the computer game off each time I came around to check. Short of sitting next to her and removing all remotes, this trust thing is what I count on for her to get her work done. She's thirteen now and I feel that it's her task to stay on task. The more I trust her, the more she will feel trustworthy. (Also I find that this is a good year to allow for mistakes in the curve of self-determination, before things "count" for college.)

After lunch, we headed out to our local hardware store to pick up some supplies for catapult building. This was for her science fair project and per her design specs, we loaded our cart with plywood, wheels, bungee cords, dowels and sand paper. I bought the supplies, but she'll build it on her weekend with her Dad. The timing on that is random, but fortuitous for me. Building catapults isn't my strong suit. Earlier in the day this had been my Facebook post:

Me: Anyone ever built a catapult? I'm supervising.
Sue: I'm curious...what is being flung?
Me: My ability as a capable parent. Oh, you mean by the catapult? A tennis ball.

As the afternoon wore on, I called out to Milly that although we were supposed to go shopping, we wouldn't have time to go if Sofia was picking her up at three to see the apartment. She looked sheepishly down at her hands, then back to me, weighing the gravity of what she had to tell me. I could sense trouble ahead, but I just waited for her to speak.

"Uh, it turns out we can't go see the apartment today, but Sofia wants to take me shopping."

"She does? But I thought I was going to take you."

"Well, she thought she was taking me, so I said I'd go."

"Oh. Well, ok I guess. I would have taken you, but that's fine."

To the average reader, you might think, what what? What's the big deal? But Mothers will probably understand my momentary angst. The shopping was for bras. Of course I'd bought her bras before, but this was different. These were to be professionally fitted. It's one of those rights of passage, a developmental milestone both physically and symbolically. And I was yielding it to my daughter's other Mother.

Sharing a child isn't as risk free as it might seem. Sure I can appreciate that my daughter has extra people loving her, and she gets to have a different perspective in parenting, but there's a small selfish part of me that still wants to dominate all the highlights. I don't want her going to her younger, hipper Mom to talk over things that might be awkward with her old Mom. But as I said, that's just the selfish part of me. The wiser me knows that having two Moms just makes growing up that much more cushioned. And having two perspectives just adds to the depth of understanding that my kid can have in the long run. And, most of all, I know that, both of us Moms love her. And that has to be good.

As she headed out the door to get in Sofia's car, she turned to me, hugged me and said, "you're still my Mom silly."

And I felt that; Motherly, and silly. Catapulted right back into cooperative parenting.