Abel was killed before he had a chance to marry.
Genesis doesn’t name Cain’s wife, but he had one, a la Genesis 4:
16Then Cain went out from the presence of the LORD, and settled in the land of Nod, east of Eden.
17Cain had relations with his wife and she conceived, and gave birth to Enoch; and he built a city, and called the name of the city Enoch, after the name of his son.
