Affairs are the musky, secretive stuff of playwrights' dreams. They feature hidden selves, assignations and unmaskings, and few characters are so dramatically compelling as the interloper, the transgressor, the mistress threatening convention or the married woman having a fling - ideal anti-heroines all. Theatre loves a bad girl. So maybe it isn't surprising that no fewer than four of them are on stage in London at the moment.
The first part of a Pinter double-bill at the Comedy theatre, The Lover, sees a husband and wife acting out adulterous role-play with each other, with Gina McKee powerful, playful and witty as Sarah. In the second play, The Collection, you really do hope that her Stella, whose supposed affair provides the catalyst for the plot, is getting around a bit - her only choice appears to be between an insecure, bisexual husband or a fey, vain boy.