At this stage of life

Cynthia Nixon of "Sex and the City" on life-long commitment without marriage, her latest Broadway project and what "Sex" has meant to the single woman.

By Frappa Stout

This week Nixon (pictured), Kristen Johnston, and Jennifer Tilly bring Broadway's "The Women" to PBS.

If a person in a relationship cheats, is it a deal- breaker? Who better to answer the age-old question than the "smart one" from HBO's "Sex and the City"? "Not necessarily," answers Cynthia Nixon, who plays hard-nosed lawyer Miranda Hobbes. "There are so many different scenarios, it's hard to know."

Nixon wouldn't know in real life. The insightful actress, 36, lives faithfully with her longtime boyfriend, with whom she has a daughter. But she gets plenty of infidelity dish in her award-winning show. In last season's cliffhanger, she reminds us, über-swinger Samantha (Kim Cattrall) went incognito and discovered her beau, Richard, in bed with another woman. "He'll be back," Nixon hints. "But I don't know what Samantha will do."

The fiery redhead faced the cheating demon head-on last winter, as star of "The Women" on Broadway. The revival of Clare Boothe Luce's malicious 1936 comedy about -- you guessed it -- women had critics in a tizzy and sold out its three-month run. It's now on PBS (9 p.m. ET Tuesday) as part of Thirteen/WNET New York's Stage on Screen series.

Nixon leads the ensemble as jilted socialite Mary Haines, Norma Shearer's role in the 1939 film. Instead of Joan Crawford and Rosalind Russell, she squares off with Kristen Johnston and Jennifer Tilly -- no less biting, but flashier in Isaac Mizrahi's lush costumes. Through their cattiness, Mary learns that her husband is cheating. Although it's still a relatable scenario, Nixon believes women have come far since those days: "We can breathe a sigh of relief that we've gotten past a lot of it. But the way Mary learns to find real friends -- that's a lesson women nowadays are learning."

No doubt thanks in part to "Sex and the City", which returns for its fifth season next month (delayed by Sarah Jessica Parker's pregnancy). With their tell-all Sunday brunches and frank sex talks, the feisty foursome could give even the wildest sorority a run for its money. "We hear from women all the time that, by watching these single women with their girlfriends, it makes them seem legitimate, that it's an OK existence," Nixon says.

But it's a foreign life to her: The Barnard College graduate has been hitched, in all but the legal sense, to college English teacher Danny Mozes for 15 years. The two met in junior high, started dating in college and now share a Manhattan apartment with their 5-year-old daughter, Samantha. Nixon has no plans to tie the knot, and most people in her life are OK with that. "That's the nice thing about having a kid -- people stop asking when you're getting married!" she says. "It's like, 'Oh, it's too late for you now.' " Nixon's own parents split when she was young, but she swears it was their marriage, not the divorce, that led to her decision not to marry. "Kids know when you're not happy. So many of my friends' parents stayed together because of the children, and my mother left because she didn't want to do that to me."

Like her Mary Haines, the blue-eyed actress has an edge. "Cynthia reeks New York, but she also has this gentle, sensitive, motherly quality," says Women director Scott Elliott. "It's kind of an ugly story, and it takes a lot of potshots at the sex. But Cynthia caught the satire without losing the audience."

That's because Nixon was a prolific actress long before "Sex and the City". Like Sarah Jessica Parker, the native New Yorker is a former child star. She started in an ABC Afterschool Special, made the racy movie "Little Darlings" with Kristy McNichol in 1980 (at 14) and did "The Philadelphia Story" on Broadway the same year. Theater vets still talk about the time she performed in two shows, "The Real Thing" and "Hurlyburly", simultaneously by racing back and forth between scenes.

"She has no star attitude," says Jennifer Tilly, her co-star and trashy nemesis in "The Women". "Poor Isaac had his hands full doing the costumes, with 26 women asking for alterations. Cynthia had one outfit she wasn't happy with but wouldn't say anything because she felt it was Isaac's concept."

Nixon co-founded her own theater company, the Drama Dept., in 1996. She's earned two Golden Globe nominations for "Sex" and a Tony nod for her 1996 play "Indiscretions" (she dyed her hair its signature copper-red for the awards ceremony). But her work often is overlooked, Tilly says, because "she's not grandstanding. She's just really, quietly, elegantly good."

When it comes to a cheating lover, Nixon would break the silence. "I'd talk to him about it much sooner, and fight it out or whatever," she says. "If you want to stay together, you work it out."