>>714432420
It's pretty clear why. She's got a hangup about her being a mutt. Marcille is likely infertile since she's a half-breed, but on top of that she has a longer lifespan than a human but a shorter lifespan than an elf. So any human lover she could have would age and die before she reached menopause and any elf lover she could have would live another 300 years after she dies from old age.

That's why she does this.