When I ride the New York subway, I'm the envy of most guys around me. I'm ruggedly handsome and have an understated sense of style (it seems I've perfected the sexy just-got-out-of-bed look) and I often have a big grin on my face—one that is inevitably triggered by the smart, sexy, funny woman at my side. On the face of it, we're picture-perfect. We banter; we flirt; I make her laugh like no other man can—at least, not on public transportation. It looks like a devastatingly irresistible dynamic. But not many know how devastating it can be.

You see, I'm the gay best friend. Eric McCormack, Paul Rudd, or Rupert Everett have played versions of me in movies and on TV. Or maybe you've seen someone like me on the street, arm in arm with an adoring woman, grinning at a private joke. It's the kind of friendship that has great perks. There are the late night calls after a bad date and the early morning boasting after a really good one. There's the reliable ego boosting—"Bald is the new black!"—and the hours of bad TV, usually ending in a heated debate about who's the sexiest man on Grey's Anatomy.

The connection between a gay man and a straight woman is one of the most exciting permutations of any relationship. It allows both parties to revel in the thrill of a close rapport with the opposite sex—without the pitfalls that often (OK, always) accompany dating. But though the dynamic is rewarding, it's rarely simple. Because friendships between gay men and straight women do not adhere to the strict guidelines governing physical and emotional intimacy, it's easy for them to impede the development of healthy romantic relationships.

Take Will & Grace. One of the sitcom's primary contributions to popular culture was its ability to candidly portray the feeling of being in love with one's best friend. As the title characters slipped into codependency worthy of an all-consuming romance, they found it increasingly difficult to cultivate meaningful relationships with other men. And because the list of women I've known and loved is—sadly—twice as long as the list of men I've loved and slept with, I, too, have fallen prey to what I've dubbed the "Will & Grace dilemma."

According to Jamie Bufalino, sex columnist at Time Out New York, straight women and their gay best friends may really be too close for comfort. "What it comes down to is that both gay men and straight women often have really hard experiences with men," he says. "But it's harder for straight women in these situations. Gay men might be experiencing emotional attraction, but straight women have to deal with the physical attraction as well."

Lara Smith*, 23, can attest. The Brooklyn-based teacher forged a fast friendship with Thomas Lloyd*, 32, her gay coworker, but soon found herself pushing the boundaries of their relationship. She constantly called and sent text messages, which were reciprocated and encouraged. "Pretty soon I was telling him details I wouldn't tell anyone else, going to his apartment daily, even helping him with errands," she says. The two stayed close for almost two years, often ensconced in the intimate space of Lloyd's studio apartment; both sometimes felt that the only thing missing from their relationship was sex. Intellectually, Smith understood that Lloyd was gay, but found it impossible to wish he wasn't. Eventually the lack of emotional and physical satisfaction caught up with her, and she started to feel used, disrespected, and misunderstood—and increasingly unsuccessful in the dating scene. "In the end, we had to 'break up'—at least temporarily," she says.

A physical split is a good way to create emotional space in the friendship between a gay man and a straight woman—but sometimes a bit of self-analysis can do the trick. Though Ari Karpel, a 35-year-old gay man and life coach, always had female friends, he realized early on in his coming-out process that many women put him on a pedestal. "They were fans more than friends," he says. Then he met Elisa Zuritsky, 37, a straight woman who worked as a writer for Sex and the City. They spent hours sharing intimate aspects of their lives; their friendship became a platonic love affair. "I would go to every black-tie event with her like a boyfriend would," Karpel says. "One weekend, I was flown first class to Los Angeles. I remember putting her dress out on the bed at this fancy hotel and feeling like a handmaid, wondering how I had become the fan." In adoring and idealizing Zuritsky, Karpel had become dependent on her for the deep intimacy that he couldn't find with a man. Years have passed, and though he jokingly referred to himself as "Elisa's ex-boyfriend" during her wedding toast, he is finally dating a man who, as he puts it, "is completely ready" for full-blown intimacy.

While it is possible to engage in both a gay/straight friendship and a requited romance, the balance can be thrown off by lofty expectations. Straight women may find that their gay male companions provide them with a level of understanding and emotional support that does not exist in the straight male psyche. And it is here that stereotypes can ring true. Whether it's a shared love of shopping or show tunes or the way he listens to stories about her evil coworker, a gay man can provide a woman with a degree of attentiveness that may be impossible for a straight man to match. "My friendship with Thomas helped me see how important comfort is in a romantic relationship," explains Lara Smith. "I know now that it's not easy to come by, but it's something I want in my next relationship." And while the gay/straight relationship may leave both friends pining for a partner that does not exist, it can also encourage them to aim high. "The best thing about being in a relationship with a gay man is realizing that I actually deserve to be treated really well," says Smith.

After a lifetime of unfulfilling—and often damaging—relationships with straight women, I now see that happy endings are possible for friends who care enough about each other to set boundaries for themselves and their friendship. Maintaining those boundaries is crucial to healthy, mutually fulfilling companionship and the key to forging an actual romantic relationship (sex included!). I, for one, would trade a million giggle sessions with a hot woman for one real night with a gay man.

*Names have been changed.