Her antagonists (a Fairy Queen and Prince) make her an offer: either Bethany never returns to Otherworld (and be another Lost Girl, like Dorothy/Alice/Wendy), or she could return as much as she wants. On condition, though, that she'd be the antagonists' "shared companion"
This conflicts and breaks Bethany, but she refuses to be the Fairy Monarchs' companion.
Bethany has embraced her bisexuality and found her love interests (a man and woman). But the Fairy Monarchs try to lure her to them, tempting her through her Oedipal/Electra complexes and the allure but sinister form of adulthood that Beth both fears and secretly desires.
And in Jungian/Freudian psychological terms, the Fairy Queen & Prince are both Bethany's shadow self and negative animus.