Abigail was once pursued by Charles Darlington and though she could have lived in the big manor and been part of high society she just wasn't that kind of gal and her feelings for Charles were always rooted in friendship. Nabil is much more down to earth, quite literally sometimes when he goes out researching and capturing frogs, a hobby he likes to involve Harvey in too. As Harvey gets older Abigail may begin to feel broody again and Nabil loved having a brother and wants a sibling for Harvey