I think you're making the right call...after a while it becomes more about the family.
I decided to retire this year (25 years) for much the same reason...I was looking at a move to California, which is simply too far to commute to on the weekends
I will have two kids in high school next year, my wife has a great career in a critical area of technology and I am looking forward to the next set of opportunities
Congratulations on 20 years of service. Outstanding!