Its not quite that simple lol
The idea is Cynria hates her mom for being a whore, even though its kinda the reason she exists, so she wants to get the hell away from her. Cynria hunts all the time, sells what she can and saves as much gold as possible in the hopes she can buy a place somewhere else.
Its actually hunting that's the reason she comes across Sharith, she chases some game too far into the forest and ends up in the succubus' territory, and ends up with the cock as the consequence.
I'm going with the idea people being marked by succubus and demons aren't unheard of, but human's think they are dangerous and cursed. This means Cynria has the sexual desire of two genders combined thanks to succubus mischief but no one in her village will fuck her, which means her only option is her whore of a mother.
Galatea doesn't mind having sex with her daughter due to them not really having a family bond ,but she demands payment like any whore would. Cynria has no choice but to use the money she was saving to get away to relieve her urges, and her mother reminds her of this every time they mess around.
It's her personal payback for all the insults from Cynria for being a whore in the first place