"Any job is very separate for me ... I love being consumed by a part that I'm playing," Parker told PEOPLE

Sarah Jessica Parker‘s newest role involves playing a woman whose marriage is falling apart — but art doesn’t always imitate life.

Speaking to reporters at the New York City premiere of her HBO show Divorce, the actress opened up about what it’s like playing someone with a troubled relationship while she herself is happily married to Matthew Broderick in real life.

“What I do on screen doesn’t cross the placenta, do you know what I mean?” she said. “I play all sorts of parts that I suppose one would wonder — but that’s my job, that’s what’s interesting to me, that’s why I wanted to tell this story and that’s why I was originally interested in this idea and finding writers who could create a tone and an environment and a landscape that would be interesting and exciting.”

Parker, 51, also said that it’s easy for her to keep her professional and private life separate.

“You know, any job is very separate for me — it always has been,” she said. “I love being consumed by a part that I’m playing.”

“I don’t relate to it,” she added. “It feels so specific.”

Credit: Gilbert Carrasquillo/FilmMagic

Gilbert Carrasquillo/FilmMagic

But that being said, that didn’t stop the star and her husband from running her lines together, with Broderick taking on some of Parker’s costar Thomas Haden Church‘s toughest zingers.

“It’s kind of fun — and also, it’s fiction, you know,” Broderick told PEOPLE at the premiere. “I thought it wasn’t really mean, I thought it was bad-tempered. It wasn’t sadistic or anything like that. It’s uncomfortable, but I think it’s saved because it’s funny and human.”

Broderick, 54, acknowledged the issue of divorce is a tough one, but also one “that’s on a lot of people’s minds, unfortunately.”

“[The show] does expose some of the uglier sides of marriage,” he said. “But it’s also humor — it’s funny.”

And according to Broderick, it’s humor that makes their marriage and life at home work with son James, 13, and twins Loretta and Tabitha, 7.

“It definitely helps,” he said. “For me it’s essential. Humor is a great diffuser with 7-year-olds and a 13-year-old!”

Parker also acknowledged her husband of almost 20 years is “fantastic for so many reasons.”

“I can’t pretend to put together an anecdotal laundry list,” she said. “I don’t usually talk about it, so it’s nice and a mystery!”

So did the couple ever sit down with the kids beforehand to let them know Mom was working on a project about divorce?

“Maybe I should have, but I have not done that,” confessed Broderick, quipping: “I avoid pretty much anything that might be difficult.”

“I’m pretty good with the kids, I think,” he added. “I haven’t told them about this show. James … he’s so smart and reads everything. I’m sure there’s nothing for me to tell him.”

Divorce premieres Sunday at 10 p.m. ET on HBO.