The Relapse

The Relapse (subtitled, Virtue in Danger) is a Restoration comedy by Sir John Vanbrugh, first performed in 1696. It re-uses characters from Colley Cibber's successful play, Love's Last Shift, which had come out earlier in the same year.

Warning: wikipedia contains spoilers

Loveless, a rake, has settled down to marriage with Amanda, but, on a visit to London, he is seduced by Berinthia, whose ex-lover, Worthy, hopes to take Amanda from Loveless. However, she remains faithful. Other characters include Lord Foppington (Sir Novelty Fashion), who hopes to marry Miss Hoyden, an heiress. However, his younger brother, a spendthrift, wreaks revenge on him by impersonating him and marries Miss Hoyden in his place.