By Rebecca Walker, RealSimple.com

(RealSimple.com)  -- Recently several dear friends have written to tell me of their number twos on the way. Each note registers as a tiny shock to my system.

I saw these children coming; I expected them in the natural course of things. But I always thought I would respond with my own exclamation, my little bit of thrilling news.

Not long ago, these joyous announcements would have laid me out flat with envy; I craved another baby and couldn't imagine my life would be complete otherwise. The dream of two (or even more) children, of spending years at a time with those small, warm bodies and soft, shiny faces, wouldn't let me go. Even now I struggle to be at peace with my decision to remain a mother of one.

I came late to motherhood. Like many of my peers, I spent most of my 20s and 30s traveling to faraway places, working hard, and falling in love over and over again. I felt I had thousands of miles to travel -- endless terrain to cover, really -- before seriously considering the topics of marriage and children, and of that thing people my parents' age spoke of: settling down. This concept seemed totally alien to me. I could not imagine the bone-deep satisfaction of living to nurture someone else.

Then I fell in love again. Glen, the man who became my life partner, wanted to have a child with me.

"He or she will make your life bigger, larger than you ever thought possible," he said one night over dinner. "Are you ready?" It was as if I had been waiting for that moment all along. I said yes.

My son, Tenzin, was born a little over a year later -- flip-flopping for 10 or 15 seconds on my breast before being whisked away by the nurse -- and my life changed beyond measure.

Of course, motherhood has not been all gardenias and rainbows. Think of the diapers. The sleep deprivation. The feeling of being eternally on call.

I have had to shrug off a sense of failure at handing Tenzin over to his father. I have asked myself (over and over) the unanswerable questions of mothers and fathers everywhere: Am I any good at this? And is there any way I can save this sweet, vulnerable child from the horrors of the world?

My difficulties and self-doubts aside, Tenzin, who is now five, has transformed me. His laughter cracks my face open with gratitude. Sharing time and space with this person is my greatest joy.

These days, Tenzin dresses himself. He brushes his teeth. He says no. (Quite a bit, too.) He runs off to play with his friends, without looking back.

About six months ago, when I packed to go on a trip, Glen praised my organizational skills. My prowess in this area will serve our son well when it is time for college, he pointed out.

I was undone by the remark because I could foresee that day so clearly. In an instant, I pictured the laundry bag I would buy someday for his dorm room. I imagined Tenzin's frame -- tall and broad like Glen's -- lumbering in and out of the room as I sorted his belongings into piles.

That night the dream of having two children revisited me. And cuing a conversation we'd had many times before, I told my husband, "I want another child." When Glen didn't respond, I said, in a voice both trembling and insistent, "I should have more children, enough to fill a house."

Glen soberly answered, "Yes, but..." and began to list the obstacles. He started with fertility. I am 40, and it is more difficult now. At my last exam, my gynecologist told me I would probably need to follow an aggressive drug protocol.

I know the medications might work, but they make me uncomfortable. I don't wish to push my body that hard, forcing the issue. I respect the choice for others, but it's not for me.

Then there is the nasty, shameful issue of money. Glen reminded me of a recent night out. Over supper, a friend groused about his son's private-school tuition. "Fifteen thousand dollars?" I asked, wincing. "Try $32,000," he said, shaking his head. "I send every bit of cash I have left over to the school," he added.

Glen and I were aghast. There are many good public schools, but that large number -- $32,000 -- represented more than the cost of education. It represented the truth of the equation, the hard facts of raising children in this world.

Then, too, in the voice I didn't want to hear, almost refused to hear, Glen wanted to know where he figured in the future I had imagined. He had given up so much to father our child, and he manages many parenting tasks that I cannot.

He cares for our son while I write and during the stretches when I travel for work. And even when I'm at home and available, my husband is essential: Unlike me, he remembers things.

That night he said it even more clearly: It wasn't fair to ask him to do more child rearing. He had his own ambitious and time-consuming dreams: He wanted to raise money to build a school in Cambodia and to make a film and have the time and energy to promote it.

From where he stood, it was a dangerous proposition to bring up the subject of a second baby again and again. Glen wanted me to be happy, but he simply did not want another child.

A few weeks after that conversation -- following many sleepless nights and internal struggles -- I decided to give my dream child up. I imagined saying good-bye to her (or him), as though I was putting the baby up for adoption. I pictured the new parents arriving at the hospital, watched them park the car and walk, excitedly, up to the revolving door. I couldn't run to her and take her home myself.

Now and then, when I cry about the choice we've made, Glen soothes me.

"Maybe there's a chance we can adopt someday, when life is easier, less busy, less demanding," he says. "When money is less of an issue." I cannot imagine a day like that.

But then I think, Who knows? Glen was right about having a child. Maybe he'll be right about adopting someday. Or perhaps in another lifetime I will meet my other child, the one I won't be having. Or she will come to me in a dream in this life, and we will live together every night, after I fall asleep.

Yes, I say to myself, yes. It isn't that she doesn't exist. It is just that she lives on the other side, and I will visit her and love her there.

Aaah-it's like a chapter from The Handmaid's Tale, and it breaks my heart to read this propaganda.