Is the idea of sexual identity relatively new?

The first time the lads slept together was in 1864. Teenage soldiers in the Union army, Hubbel Pierce and Alonzo Choate met on the march to the South and fell for each other, brothers in arms. When they returned to their lives as homesteaders in Michigan, Pierce gave Choate a ring. In letters they called each other “beloved husband” and joked about their sex life. Relatives joined in the teasing. In one letter, Choate’s sister wrote a postscript in which she referred to her brother as Pierce’s “wife”.