This one is AH, set in the Victorian era:
Teach Me How by dampersandspoonsWilliam Hawthorne, cir. 1878 is a womanizing aristocrat. He's content with bedding as many women as possible with no intent to marry. Elizabeth Summers is a stubborn young girl who is constantly protesting against the lifestyle that her wealthy family expects of her. When both characters' parents arrange them to be married, will William find his match or will Elizabeth scare him away, as she has all her other suitors? (Super smut eventually. Spike is a bad, rude man, after all!)In this one Buffy and Spike travel time back to the Victorian era:
To Save a Lady by SlaymesoftlySpike and Buffy are sucked into an Initiative time machine and find themselves in 19th century London. Somehow, pretending to be husband and wife seems to be the way to go....