Plays parsing the viability of monogamy are nothing new. The “sacred” tie that binds “one man and one woman” have been under scrutiny since the mythic Adam and Eve stumbled out of the garden shortly after their creation and subsequent fall from grace. The current hype about the sanctity of heteronormative coupling makes the issue even more relevant despite the historical interest in the construct. There is, however, something new and engaging in Bess Wohl’s “Grand Horizons” which is currently playing on Broadway at Second Stage’s Hayes Theater.

After being married for fifty years, Nancy (a stoic and enlightened Jane Alexander) and Bill (a stolid and dependable James Cromwell) have settled into the routines of matrimony as do most other couples with some longevity in their relationship. At the beginning of “Grand Horizons,” (the name of the independent living community for seniors where the couple live) the pair are moving through the paces of the highly choreographed and oft-rehearsed ritual of sharing a meal. They appear disinterested and dispassionate about the whole affair until after Bill gets Nancy a back pillow for her chair, Nancy declares, “I think I would like a divorce” and Bill replies, “All right.”

As might be expected, Nancy and Bill’s two sons Brian (an energized and conflicted Michael Urie) and Ben (a reserved and self-centered Ben McKenzie) and Ben’s pregnant wife Jess (a dynamic and richly confrontational Ashley Park) descend upon their parents demanding to know why Nancy wants a divorce and why Bill resigns so easily to her request. Amid the protestations and defenses, it becomes clear that the progeny might be more concerned about themselves than they are about their progenitors’ fates. As Bill continues to pack and Nancy moves forward with her plans to attend a conference out if state, the siblings’ (plus one) panic increases exponentially. Bess Wohl’s dialogue here is exquisite and Jane Alexander’s comedic timing consistently steals the show – and not because of the body part vernacular that unfortunately abounds in the script.

Under Leigh Silverman’s meticulous direction, the ensemble cast could not be better poised to ensure the success of “Grand Horizons.” Bess Wohl develops her characters with precision which allows the cast members to dig deeply into their portrayal of the characters. The audience sees Nancy and Bill from so many points of view – including their own – that there is no doubt about what has motivated them throughout their marriage. Ben is characterized through his wife Ashley. And although Brian is not married, he is cleverly characterized in the early encounter with his pick-up date Tommy (a manic and transparent Maulik Pancholy). Bill’s “girlfriend” Carla’s (a nonplussed and inculpable Priscilla Lopez) unexpected visit with Nancy reveals much about Bill’s undisclosed needs.

Although the cast often outshines the script, Bess Wohl successfully raises rich and enduring questions that transcend cultural and generational divides. What are the responsibilities of parenting and when do these responsibilities end, if ever? What are the responsibilities of children for their own destinies and why is separation-individuation so difficult in American society? Is monogamy sustainable? Is the only alternative to monogamy open marriages or are there better ways to form support communities that also engender population growth?

Perhaps Bess Wohl is reminding us of what some anthropologists have suggested for quite some time: parents are responsible for their children through adolescence and not beyond and children are not responsible for their parents once they leave home. Nancy and Bill seem to be able to resolve their misperceptions and differences on their own and after their children give them the space they most likely needed all their post-parenting lives. Addressing Brian, Ben, and Jess, Nancy suggests, “If I can offer a little maternal advice? I would focus on your own lives. (To Ben.) You have a baby coming. You should probably get things straightened out before then.”