Rachel is a writer whose new novel is about to be published. Her husband, Richard, used to run an experimental theater and now, without undue sourness, runs an artisanal pickle company. The couple live in a cluttered, cozy apartment on an East Village block not yet overrun by money. They are literate, witty people (played by Kathryn Hahn and Paul Giamatti) who might rather be smart than nice but are generally pretty nice anyway, even to each other. Their mutual prickliness is a sign of long intimacy, as if they were two cut-to-match pieces of sandpaper. Over the years of their relationship — he’s 47, she’s about a half-decade younger — neither one has been too badly scraped up or smoothed out by the other.

It’s a happy marriage, in other words, though one that is touched with midlife melancholy. Contentment and disappointment sit so close together on the spectrum of shared experience that it can be hard to tell one from the other. The one thing that’s missing from Rachel and Richard’s lives — the pursuit of which gives “Private Life,” Tamara Jenkins’s piquant and perfect new comedy, its shape and momentum — is a baby.

A heartbreaking adoption near miss lies in the recent past, and they are in the midst of a long, fertility-treatment roller-coaster ride when we first meet them. Literally in the midst: The opening scene is of Richard administering an injection to Rachel’s backside. But while “Private Life” has funny and heartfelt insights (as well as some potentially useful information) on modern technologically assisted reproduction and its discontents, the movie is not only or even primarily about fruitless efforts to multiply. Someone once said that life is what happens while you’re making other plans. This movie is about the plans that happen while you’re trying to make another life.