Brelyna Maryon was Crotch Guzzler's college girlfriend, and he had sex with her. He killed her, when destroying the College of Winterhold.
Brelyna was Crotch Guzzler's girlfriend in college, whom he had sex with. He remembers their relationship as a 'mistake', and finds her to be very ugly, after having sex with her. He recruits her as a follower. She was killed by him, when he murders everyone in the College of Winterhold.
Crotch brings her corpse back to his home, to teach his children that everyone makes mistakes, and that there are more fish in the sea, and Brelyna, was both his mistake, and his first fish.