"it was The Fatal Marriage"

Aphra Behn
Public DomainAphra Behn - Credit: George Scharf (1820—1895)
The Fatal Marriage, or the Innocent Adultery, was a play by Thomas Southerne (1660-1746), an Irish dramatist who lived in London from 1678. His first play, The Persian Prince, or the Loyal Brother (1682), was based on a contemporary novel.  The Fatal Marriage was a sentimental drama published in 1694.  It was based on Mrs Aphra Behn’s The History of the Nun, with a comic underplot added by Southerne.