Birds don't intellectualize relationships the way we do. Many will be faithful to a mate as long as the mate is there, but if the mate disappears and their hormones are running high, they'll mate with someone else. This is how nature keeps the species going.
If Bio came back again, she might very well dump Georgie and go back to Bio. A study on force re-paired cockatiels (where they were separated from their free-choice mate and put in a breeding cage with a mate they didn't choose) found that some would breed with the new mate, especially if both birds had previous breeding experience. But many of them went back to their old mate when they got the chance.
http://www.appliedanimalbehaviour.com/a ... 8/abstract