hey SABmore, so my experience is very much the same as yours. Granted I was a little younger when I started (28) I was in the same boat, mortgage, wife and great job I didn't want to give up for nothing. So I decided I would make it work. At this point I should note I have been blessed with an amazing understanding wife who has been very patient over the years. My strategy was simple, dedication in the evenings and unlike many startups by a younger founder where fly by the seat of your pants, I made a very clear plan first which took over 2 months in the evenings. This way when I was ready to start development my work was very concentrated based on the plan I had developed. In addition this proved to be very beneficial when I brought on another developer. They could be working during the day without having to call me.

One thing I will say... do it, work your butt off and it will pay off in the end!