I think that the one who qualifies the best would be Merope Gaunt, Voldemort's mother. Born in utter misery and in a family of degenerated, ultra-violent and completely insane pure-blooded supremacists with her father and brother being super abusive toward her, having no friends or anyone to sincerely care for and having fallen with the rich snob and prick Tom Riddle Sr, her whole life was nothing but pure tragedy and misery.
While her use of a love potion to force Tom Riddle to marry her and have a baby with her was purely immoral it's not surprising that she was so desesperate for love and had no idea of how reprehensible her action was due to the utter lack of education, her loneliness and the terrible abuse she suffered, and it's even less surprising that she didn't had the force and will to live after he left her after she stopped using the love potion., only living long enough to give birth to her son.