When We Are Married. Set in 1907 in Yorkshire, where J.B. Priestley grew up, When We Are Married focuses on three status-conscious and conventional middle-class couples who were married in the same ceremony 25 years before and have reconvened to celebrate and pose for a commemorative photo. Also on hand is Gerald, a young man who's courting the niece of one of the husbands, as well as a couple of servants — a drunken, hostile charwoman and the far less prickly and generally ignored teenage maid. A reporter and a mouthy photographer intrude on the action now and then, as does a free-spirited tootsie who once had a flirtation with one of the husbands at Blackpool. The plot is flimsy. The couples discover that because of a minor technicality, their marriages aren't legal, and this gives them a chance to re-evaluate their relationships. Timid Herbert Soppitt is routinely ordered about by his shrewish wife, Clara; Annie Parker has grown tired of Albert, her stingy popinjay of a husband; and while the Helliwells appear to enjoy an occasional moment of communication, their marriage seems held together more by habit than anything warmer. Given the time and place they live in, however, these folks don't have the option of divorcing and creating entirely new lives — although we really want them to, because the script hints at possibilities of true love and transformation with just a little partner-swapping. The production is sumptuous, and the set and costumes (by Vicki Smith and David Kay Mickelsen, respectively) deserve a round of applause all on their own. Still, the entire enterprise feels a bit tired and dated, and you can't help feeling that the Denver Center will never fill its seats or entice a new generation of viewers with period pieces like this. Presented by the Denver Center Theatre Company through December 16, Stage Theatre, Denver Performing Arts Complex, 303-893-4100, www.denvercenter.org. Reviewed November 29.