Who was Gomer?
Gomer was the wife of Hosea, a prophet of Israel.
Hosea married Gomer according to Divine appointment, and this was the beginning of God's word to him ( Hosea 1:3 ; Hosea 3:1-4 ). She was to be a wife of whoredom and they were to have children of whoredom. This need not mean that at the time of marriage she was thus depraved, but she had the evil taint in her blood, had inherited immoral instincts.
These soon manifested themselves, and the unfaithful, depraved wife of the prophet went deeper into sin. She seems to have left him and become the slave of her paramour (Hosea 3:1 ). Hosea is now commanded by Yahweh to buy her back, paying the price of the ordinary slave. The prophet keeps her in confinement and without a husband for some time. This experience of the prophet was typical of Israel's unfaithfulness, of Israel's exile, and of God bringing her back after the punishment of the exile.
IBSE (in the public domain) with minor edits.