My 8-year-old son has frequently been called an old soul; one of those kids who uses big words like ‘epitome’ and ‘antithesis’ with ease and who enjoys chatting up adults about topics ranging from the fate of the U.S. automotive industry to the inner workings of the human body. Part of this stems from the fact that he’s the oldest of four children (two little brothers and a baby sister hang on his every word). And part of it stems from just how he’s wired.

But wise-beyond-his-years though my son is, there is one situation my husband and I are still figuring out how to help him get a proper handle on: my father’s recent marriage to another man.

My son understands a little bit about same-sex couples. Some of his classmates have two daddies. And we have friends who are gay, whom he adores. But my father, my son knows, was married to my mother, a woman. And so his new marriage to another man makes things, well, complicated.

My father announced his engagement in a typewritten note. He was flying from his adopted home in Florida to New York to wed at City Hall. Would my husband and I be the witnesses, he wondered.

My father has shared details of his love life with me for years. He left my mother for another man when I was 8 and went on to bring a series of “special (boy)friends” into my life. First came Hans, a kindly German immigrant and gifted interior designer. Then came Franz (real names, both, I swear), a former member of the Vienna Boys Choir. Later came Tony, a Japanese businessman, then Shastri, an Indian-American accountant,  then Rick, an aspiring personal trainer, and Sakis, a would-be dog groomer from Greece.

My father discussed  the notion of marriage and commitment ceremonies with those men  once in a while – but, for the most part, my father seemed uninterested in formalizing any of the relationships, in large part because the relationships dissolved, on their own, in relatively short order.

It made no sense to explain my father’s sexuality to our oldest son during any of “Opa’s” visits- since he was so young and Opa was so non- committal. We never had to explain Opa’s sexuality because we didn’t think there was need to explain.

His marriage to Javier changes things.

My husband and I served as witnesses at my father’s wedding on a beautiful fall afternoon. My father and Javier wore button-down shirts and khakis and matching boutonnieres (white carnations nestled in a spray if green). I wore a rose Zac Posen dress, my husband his favorite suit. Together, we stood in New York’s City Hall,  waiting for their marriage ‘number’ to be called,  in a long corridor that reminded me of Grand Central Station: rather pretty, exceptionally crowded, with a mass of humanity waiting to move from one place in their lives to another.

When they weren’t concentrating on the number board, nervously willing it flash their number – 104 –  my father and Javier passed the time, striking up conversations with those my father happily referred to as “their people”: other same-sex couples. Among those with whom they chatted: a pair of young 20-something females who’d met in the Navy. One wore her military dress whites, the other a pretty strapless tea-length gown with a full skirt. Then there were the greying male partners in their 70s who wore crisp blue suits, matching bow ties. The dapper duo hailed from Pennsylvania and boasted sweetly to my father they’d been together for 50 years. Half a century.

My father and Javier have been together for less than a decade. They met a year into my own marriage, at one of my father’s favorite haunts, a gay bar in West Palm Beach. It wasn’t love at first sight, my father would later tell me. Instead, theirs was a companionship that grew ever-closer. My father, nearing 70 at the time, was weary of the dating scene. Javier, 30 years my father’s junior, offered my father a pair of helping hands for his increasingly-unsteady-legs, someone to remind him to take his medicine and a mutual love for their dog , Leo. For Javier, my father provided stability, friendship, and a guiding hand. A native of Honduras, he gratefully accepted my father’s offer to help him secure a teller job at a local bank.

At first, my father kept his life with Javier relatively separate from mine. He visited his grandchildren without Javier. He called me frequently and seldom mentioned Javier’s name. But then they decided it was time to legalize their commitment, to make their union official.

When the time came to say their “I Dos”, before a smiling female judge who asked them to face one another and join hands, my father and Javier joined a small, but growing, number of legally married grandpas who have grandchildren not unlike my own children, energetic young puppy dogs armed with ready smiles — and armed with something more: endless questions.

It’s those questions from my 8-year-old in particular — about marriage, about how Opa’s marriage to Javier differs from Opa’s marriage to my mother or how Opa’s new marriage differs from mine and Daddy’s — I’m working through how best to answer.

I’m not sure how to explain to our oldest how Javier fits into the family when my father is still clarifying that for the grown ups — and when Javier and I are still figuring out what we mean to each other. I know the answers will come in time as we come together for family gatherings.

One such gathering took place following the wedding.

“How come Opa’s in town?” my son asked, as my husband and I dressed him up to take him to meet my father and Javier for dinner at an Italian restaurant, our unofficial wedding reception for the happy couple.

“He wanted to see us and he wanted to show Javier New York,” I said, helping my son with his sweater.

“Javier?” my son asked.

“You remember – Javier,” my husband answered evenly.

“Oh, yeah,” he answered. “Opa’s friend.”

“That’s right,” I said. ” You’re probably going to be seeing a lot more of him from now on since Javier and Opa mean a lot to each other.” I paused. “Okay?”

“Okay,” my son shrugged. “That’s cool.”

That night, the four of us — my father, Javier, my husband and me — opted as a unit not to explain to our oldest son, or his brothers and sisters, that Opa and Javier are officially married now. That discussion, we all agreed, will come in time. For now, I’ve come to realize, my father’s relationship with Javier is like so many marriages and families: It’s complicated.

Moments after sitting down at our table, the waiter presented us with flutes of champagne. And as we grownups lifted our glasses in a toast, the children raised their milk glasses to join in the fun.

“What are we drinking to?” asked my 8-year-old, raising his glass high over his head as he reached to clink Javier’s glass.

“What we always drink to,” I said, looking him squarely in the eye. “To family.”

 Mary Pflum Peterson is a multi-Emmy-Award-winning producer at ABC News/ Good Morning America. She is also the author of White Dresses: A Memoir of Love and Secrets, Mothers and Daughters, which chronicles her decidedly complicated, yet determinedly loving, family.