There were times when my husband would call his ex-wife and tell her how much the kids wanted to see her. He would beg her to see the kids. She lived 20 minutes away; sometimes she would come pick them up for an hour, but quite often she wouldn't. The kids could never understand why she didn’t want to be with them. I never could either.

We did not have the typical custody arrangement. My husband and his ex-wife had 50/50 custody, and each parent was supposed to have the children a week at a time, but after the first week (long before I was in the picture), the kids' biological mom no longer wanted that. The arrangement was modified so that she could see the kids whenever she wanted, had every other holiday, and could be there for birthdays and other events. After the first year, she stopped taking her share of holidays, and I'm not sure the kids even remember her at birthdays.

As step mom, this meant that I didn't have to share – that I didn’t have the challenge of step kids spending more time with someone else raising them where my influence and time was limited. In fact, the kids were with us all the time. It was like they weren't steps at all.

On those rare occasions, then, when the kids saw their mother, I experienced fear – fear that something about our arrangement would change – that the kids would suddenly decide they wanted to live with mom, or mom would suddenly realize everything she had been missing and want her (my) kids back.

We have been lucky in a lot of ways because we haven't had that strained back and forth with the kids, and the kids have not ever had to learn how to live in two households and follow two sets of rules. They've never come home after a weekend at their moms full of ideas about how things "should" be or had anything to say about "mom does it this way."

For all intents and purposes, I've been mom, something that has been a real pleasure and a real privilege.

The sad truth is, though, that even though I filled the gap and have a great relationship with my step kids, and even though I was there for the kids for broken bones and straight As and broken hearts and everything else, they want their mom. I don't feel slighted by this – but my heart breaks, knowing that this woman who has three marvelous children in the world has opted not to know the fabulous people they are becoming.