I remember asking Bob's mom once how it was she raised six kids. She said, without hesitation, that once you had three kids, adding more was less work. The older kids help with the younger kids. She never had to worry about playdates. Her house was a hub of activity whether the neighborhood kids were congregating there (they were) or not. Her home wasn't a page out of a Pottery Barn catalog, but the last time I checked there weren't a lot of pictures of happy families on those pages.
Family is about knowing you are loved, feeling safe to be yourself, a place where judgement is rare not the norm, and dammit, good food should be plentiful. Memories of Thanksgiving at my grandparents' home with my cousins are some of my favorite. I loved feeling like we had a great big family for that bit of time, all of us around a long, makeshift table, my cousin, Eric, and I seated at the piano bench, anchoring the stern of the feast.
There is no magic number that defines a family. Did I think mine would grow to include more children after Bob died? I had no idea, but I am so thankful it did. I can't imagine life without our bonus family.