I am the product of a mixed marriage - Mom Dodgers, Dad Giants.
When they left, my Dad took me to Philadelphia a couple of times to see the Giants, and we went to a few Sunday doubleheaders at the Polo Grounds in 62 and 63, but by the time Shea opened we were pretty much Mets fans.
My granddad never did settle on a new favorite but he did watch every Indians game that came on TV. My Dad finally settled on the St Louis Cardinals. I just watched whatever they were watching.