However, I will not be taking into account the Greco-Roman and Mesopotamian stories as they are the only stories that I know of in which a goddess loves a human.
There are a couple that I could find.
Clídna, the Irish goddess/Fairy Queen, had an affair with Ciabhan, John Fitzjames, and Earl Gerald Fitzgerald, among others.1
Bai Mudan was worshiped as a goddess who tempted men with sex. It's not quite love, but it's close. Wiki
The West African Mami Wata spirits are analogous to Greek nymphs. They seem to fall in love, not just want sex, too.
Saxo mentions that Frigg slept with a servant, but Saxo had a Christian agenda and stated up front that he believed Frigg and Odin were actually people, not gods.
In the Irish tale The Sickbed of Cuchulainn the hero has an affair with Fand, a fairy woman. It ends unhappily, as the otherworld and this world cannot be together. Fand returns to her husband, the sea-god and magician Manannan mac Lir, and Cuchulainn goes back to his wife, Emer. To make sure they never meet again, Manannan shakes his cloak between Cuchulainn and Fand.