The passage in Genesis 1:27 " "So God created man in his own image, in the image of God created he him; male and female created he them" (before describing a mate being made of Adam's rib and being called Eve in Genesis 2:22) is sometimes believed to be an indication that Adam had a wife before Eve.
A medieval reference to Lilith as the first wife of Adam is the anonymous The Alphabet of Ben-Sira, written sometime between the 8th and 11th centuries. Lilith is described as refusing to assume a subservient role to Adam during sexual intercourse and so deserting him ("She said, 'I will not lie below,' and he said, 'I will not lie beneath you, but only on top. For you are fit only to be in the bottom position, while I am to be the superior one.'"). Lilith promptly uttered the name of God, took to the air, and left the Garden, settling on the Red Sea coast.