Photo Courtesy of Laura Robbins "If I’m not his wife anymore and I’m not the only mother of his children, then who am I?" the author writes.

My ex-husband is calling me at three in the afternoon. My first thought is that something must be wrong.

“I wanted you to hear it from me first ― Kelly is pregnant.”

My breath catches in my throat and my lower jaw tightens, preventing any kind of intelligible, audible reaction.

“We just told the boys. It’s early on, so we aren’t really telling anyone yet.”

He and his wife, Kelly, are in Kona, Hawaii. On the same island where he proposed to me 20 years earlier. The two of them are there with our children ― mine and his, our sons. They delayed the trip until Dec. 26 so I could spend Christmas with the boys before they took them away for 10 days.

I’d had a feeling that they’d been doing in vitro fertilization. The boys had told me that Kelly had gone to the doctor’s two or three times on various Saturday afternoons for some urgent, mysterious appointments.

What else brings newly married couples to the doctor on a Saturday morning for more than one outpatient procedure within a span of two months? Dental implants? A colonoscopy?

It makes sense that she would want kids of her own. She’s 12 years younger than me, after all. It makes sense that he wants children with her. I’ve seen the way he looks at her ― it’s the way he used to look at me.

I hear the hum of my air conditioner starting up while he waits for me to say something. But all I can think about is how Kelly’s pregnancy is going to impact my already-fragile, oftentimes awkward relationship with the two of them. I want to just hang up and pretend that we lost the connection, but I feel his apprehension growing the longer I’m silent. The quiet on the line between us is ironically loud.

Say something, Laura.

I want to, but I can’t for the life of me remember what the standard response is here. My mind races, scrambling to recover some basic manners.

“Congratulations,” I say finally. I worry that it sounds insincere.

The fact is that when I thought they were doing IVF, I was hoping that it wouldn’t be successful. I’ve never told anyone that before, but it’s the truth. I didn’t want them to have a baby because that would mean that they had their own family ― separate from me. Since our divorce five years ago, I’ve sometimes felt like my kids are on loan to them, something to complete their little holiday card photos.

But with a baby, they’ll have their own legitimate family. A family from which I could be excluded entirely. A family which my own children might prefer.

Existentially, this idea creates a roil of panic in my gut. If I’m not his wife anymore and I’m not the only mother of his children, then who am I?

With a baby, they’ll have their own legitimate family. A family from which I could be excluded entirely. A family which my own children might prefer.

I feel my heart hardening after we hang up. The wounds from our divorce are still tender when it comes to her.

Kelly is someone I’ve known for over 20 years. She was a guest at our wedding 18 years ago. In her wedding video message to us, she states, through peals of laughter, that she’s always put our relationship on a pedestal and that she “wants everything that we have.”

For about a year after the divorce, I wanted to carry that video around with me and show everyone, saying, “See! This is what I’m dealing with.”

But I don’t want to vilify her anymore; it’s starting to feel like a cheap ploy for sympathy. Most of the time, I’d really just like to forget that they’re married at all. But this news makes forgetting impossible.

The following morning, I am overwhelmed by the urge to call my sons and see how they feel about it. Maybe they hate the idea of another sibling, maybe they too are afraid of what will happen to our family if their dad and Kelly have a child of their own. I call my oldest son’s cell phone at 10:30 a.m., convincing myself that they’re probably still on California time.

When he answers, I clear my throat, steeling myself to ask him how he feels about getting a baby sister or brother. But he blurts out, “Dad and Kelly left this morning; they’re not back yet.”

Ire wells like a balloon in my chest and threatens to burst out of my ears.

How irresponsible. How dare they leave a 10-year-old in charge of an 8-year-old?

“Left? What do you mean, left? Where did they go?”

I’m picturing my ex and Kelly hiking on a volcano tour or eating breakfast on the deck of a private boat, drinking mimosas and watching the sunrise.

“I think they went to the hospital.”

I draw in a fresh breath. Now there is a pulsing knot in my stomach.

“Why, what happened?”

“I don’t know, something about the baby.”

I hang up and dial my ex-husband’s number without thinking about it. A number I’ve memorized for better or for worse; he is still my emergency contact.

He answers on the first ring.

“Hello?”

The familiar sound of fear in his voice causes blood to rush to my head, flushing my cheeks.

“Hey, I just talked to the boys. What happened?”

I’m trying to keep my voice even.

“It’s Laura,” he says to someone on the other end.

I picture him pacing in a circle, covering the phone slightly and turning toward her as he speaks. I picture her, lying down next to him in a thin, faded cloth hospital gown on the paper-covered exam room bed.

“She’s cramping. It started last night.”

“A lot or a little?”

I hear the words coming out of my mouth, but I’m completely disconnected from my body like I’m in a brown-out.

“A little,” he says. “But it’s painful and it hasn’t let up.”

“Any blood?”

I’ve switched into “Dr. Cathcart” mode now (my father, the HIV doctor). Channeling him, I know what questions to ask, I know the power of a soft, steady tone.

“Not really, the doctor said it might be a bladder infection or something?”

His voice sounds so hopeless.

I realize that as soon as my son told me that something was wrong that morning, something shifted inside of me, something for which I still don’t have an explanation.

A vivid memory floods into my consciousness then, bringing with it a sudden wave of calm. I feel my whole body relax. My eyes soften and fill with hot, scanty tears.

I switch to the voice I use when I’m reading a bedtime story to our kids.

“Do you remember when I was pregnant the first time?” I had that same thing, remember? It was a bladder infection. Very common at this early stage. I’m sure that’s what it is. Won’t harm the baby. Totally treatable.”

“Hey, that’s right!” He sounds all choked up now. I’m imagining that he’s doing that thing again, slightly covering the phone with his hand and turning his head toward her.

“Laura says we had this, too,” he tells her. “She says it probably is a bladder infection. She says it’s going to be fine, totally normal.”

“Really?” Her voice sounds small, far away. “How long did it last?”

“Not long,” I say loud enough for her to hear in case he’s placed me on speaker.

“Tell her not to worry.”

I’m shocked to find that the tears have made their way out of my eyes and are now streaming freely down my cheeks.

“Tell her it will be OK.”

“She says it will be OK, Kelly. She says not to worry.”

And just like that, I find out how I really feel about him and Kelly having this baby. I thought that I wanted their attempt at familyhood to be a major, heart-wrenching failure. I thought that I wanted to feel the sense of smug superiority that came with knowing that I was the only person who would ever carry his child.

I close my eyes and scan my body, looking for that sharp vindictiveness that had taken up residence near my heart for the past few years. I quickly sort through memory after painful memory of my post-divorce feelings of “compare and despair,” trying to summon up feelings of contempt and a desire to see them both unhappy. But I realize that as soon as my son told me that something was wrong that morning, something shifted inside of me, something for which I still don’t have an explanation.

I want their baby to be OK. And this realization brings with it another one, one that is astonishing to me. It no longer matters what happens to me if Kelly and my ex-husband have a family of their own. Without even realizing it, this yet-to-be-born child has dispelled my self-centered fear of being displaced and replaced it with something much easier to metabolize ― forgiveness.

Do you have a personal story you’d like to see published on HuffPost? Find out what we’re looking for here and send us a pitch!