JustThisGayKid
Callie's father reaches out after the divorce with an offer. A trade. Access to the family funds again, and him meeting his granddaughter, in exchange for Callie's hand. He offers nothing more then the fact she'd be married to a woman if she accepted.
She was struggling to make bills, and care for her 8 year old, even with 50/50 custody with her ex, and she needed the funds she'd been being denied for years. So, Callie makes the choice, taking a risk. She accepted.