In an age attracted by opposing trends of cynicism and celebrity-worship what a surprise to find the National presenting a sentimental, romantic comedy that celebrates marriage.

In Lucinda Coxon's Happy Now? the course of true love runs a little rough in the life of Olivia Williams's suitably harassed Kitty, a career woman in her late thirties, who has to cope with one demanding job, two kids, a teacher-husband, Johnny, who does not kiss her any more, a sick father and a bitchily subversive mother.

Her gay best friend, portly, middle-aged Carl, created to be that demeaning gay stereotype, the queer whom married couples like to befriend, patronise and mildly insult, offers sympathy.

But Carl has troubles of his own in the shape of a young lover. So when Stanley Townsend's Michael, a fat, confident Irishman, tries to seduce Kitty, moments after they have met at a conference, she may do the decent thing and refuse his minor advances but you can see she is stirred by his proposition.

Coxon wants us to realise the attraction of the encounter: it is not romance but at least Kitty is not being taken for granted for once.

All this may sound the stuff of old, familiar cliché, and it is, but Coxon has torn off a strip of authentic, middle-class English life and given it theatrical and reasonably amusing form. The perspective, thanks to her rose-tinted spectacles, remains sunny, so that Jonathan Cullen's Johnny ends up kissing his wife as if to show that he has turned into a new husband.

The play closes with Kitty watching television. On either side sit Johnny and the estranged, alcoholic husband of their friend Beatrice, Dominic Rowan's handsome Miles, who has moved into their spare-room. A ménage à trois? Not at all. Coxon takes far too conventional view of personal relations for that. Even Kitty's eventual drunken bedroom encounter with Michael ends up anti-climactically in a pillow fight, without a whisper of sex.

Thea Sharrock's laboriously organised production scores its comic points, but is confounded by imposing a radical design upon a traditionally based comedy. Jonathan Fensom's sparse set, with a few bits of furniture in a brown-bordered, galleried open space, merely resembles a rehearsal room.

The actors, particularly Williams's elegantly put-upon Kitty, are well-tuned to this romantic celebration of new-age woman.