“In 1918, six months before the end of the first world war, Marie Stopes published Married Love. … There’s nothing about sexual problems, nor contraception (apart from one chapter), but instead, she writes about the ecstasy of fulfillment.” (The book played a key role in an episode of Downton Abbey.) She then received tens of thousands of letters asking for advice – about sexual problems, venereal diseases, and above all, contraception. Composer Alex Mills and librettist Jennifer Thorp have turned a collection of those letters into a chamber opera.