I
I only applied to one school my first go-around. There were a number of reasons. Ultimately I just really wanted to go to that one school and figured it was worth trying again the following year (and adding more schools) if it didn't work out the first time around. While I didn't get an interview the first year, I did the second time (at which time I also applied to my in-state schools--all UC's, but that's another story why I didn't finish secondaries for other programs), and they were quite impressed by my dedication. I got a direct acceptance a week later at a time they were interviewing almost entirely for the wait-list.
In hindsight it was rather stupid--at the time I had no family argument like you do, and there were other schools that I could've been just as happy at and trained to become a perfectly ok doctor at as well.
However, as someone with a spouse and family, I understand how important they are. More important than becoming a doctor. It's interesting how once we have kids of your own we realize our career aspirations aren't the most important thing in the world, like they used to be when we were younger/in college. All of a sudden other people's happiness and well-being matter more than our own. And we try to make it all work when you can (like applying to your one in-state school...).
I wish you the best of luck.