What makes Keep the Lights On very notable is what it quietly does not do, though few will notice. Seeing it as the tale of a relatively long-term gay relationship is not fully accurate. Lovers’ realistically depicted messy physical homosexuality presents no problem, their sexual orientation matters little to the New York circles in which they move, there is no message for tolerance sociopolitical or otherwise, and a brief payphone call is the sole reference to HIV/AIDS or any other bogey.

Director and cowriter Ira Sachs’s fourth feature is a love story -- autobiographical but, still, one that could as well have been about a heterosexual couple. The highs (double meaning) and lows, the intimacy and physical and emotional ecstasies and depressions, separations and reunions, parties and loneliness, infidelities and jealousies, petty and fundamental disagreements, waxings and wanings, are all part of many a relationship, period.

Not plea or preachment but a slice of life, it pictures gay people as people, same-sex couples as couples. While principals’ sexual orientation and graphic but not pornographic scenes may put off multiplex moviegoers, publicity is doing its best to bring the forty-six-year-old director’s work out of the niche-cinema closet, with local film festivals and scheduled post-screening Q&As at the Museum of Modern Art and at a “Looking for Love” retrospective of his oeuvre at the Museum of the Moving Image -- MoMA and MoMI.

The ten years of its on-again, off-again coupledom unnecessarily indicated by the trend of printed-title dates, this hermetic world faces and solves, or fails to, its difficulties created from within not without. All supportive others enter and leave, but the center of gravity is heavily weighted to closeted publishing-house lawyer Paul Lucy (Zachary Booth) and thirty-something expat Danish documentarian Erik Rothman (Thure Lindhardt).

Scraggly bearded to his younger partner’s boyish clean-shaved, this filmmaker character is always onscreen as the point-of-view entrée into this, and their, world and tempts one to see him as Sachs’s own persona.

It is he who must make a final decision, of great hurt but also of hope, after many false starts and re-starts. Prodded “to make money for the first time in your life” by loving, married-with-children-and-career sister Karen (Paprika Steen) -- they come from money -- he has long been putting together a non-fiction film briefly incorporated into this larger fiction one and in fact an arresting in-group aside. Produced and codirected by Sachs, In Search of Avery Willard covers the life of that untalented late pioneer of queer cinema (Leather Narcissus, 1980) and is now premièring separately.

The only person outside these two who stays the course is Claire (Julianne Nicholson), who at thirty-four wants a child after long bad luck or judgment in her choices of men, the most recent being already-father-of-two Alassane (Souléymane Sy Savané). She toys seriously with having Erik grant her wish, and though he is not against helping out this loyal friend, he not convinced, either.

SPOILER ALERT

The two men first meet for casual sex, but they click and decide to move in together. Paul is revealed much less, and he can be snippy, but it is his crack-cocaine dependency that worsens and drives wedges between them. Not that either is totally monogamous -- druggie dancer Russ comes along, and a nameless gigolo, and prospective Igor (Sebastian La Cause, Chris Lenk, Miguel Del Toro), and phone-sex contacts -- but the addict’s binges and disappearances grow more frequent and stress both partners. Stints in rehab and at an upstate artists’ workshop colony promise reform and reunion, but the pull of drug into relapse proves each time beyond control, until one of them has to decide to control his, and their, future.

Slightly grainy Super 16 gives a gritty urban tone and keeps this from being picture-pretty. Unerring acting keeps it honest, so that, while not tragedy, Keep the Lights On is true and far from the gay fluff or doom often offered up. The song has it that breaking up is hard to do; staying together is no walk in the park, either.

(Released by Music Box Films; not rated by MPAA.)