In Nov. 1891, the British sexologist Havelock Ellis married the writer and lesbian Edith Lees. He was 32 and a virgin. And since he was impotent, they never consummated their union. After their honeymoon, the two lived separately in what he called an open marriage. The union lasted until Lees’ death in 1916. This is not what most would consider a model marriage. But perhaps because of its unusualness, Ellis was able to introduce an idea that remains as radical and tantalizing today as it was in his time: trial marriages.