I second that. Married with kids? Don't jump off the train right away. Start your own project for fun on the side. It as to be fairly contained and not to hard to put in place because you want to minimize the time spent at your current 9-5 job. Make it grow, look at the potential, get early feedback or eventually generate a tiny income out of it (optional). Look at your savings, make a plan with a 1 year run, or 2 years if you can. Quit in good terms, tell people you're going to pursue your dream and would love to come back in the future.

Quitting a job to pursue your dream is great, but that dream needs a clear definition.

Just do not have enough time and focus (that's more important) for that. Usually I devote almost all out-of-office time to family, do not want to spend all weekends hacking =). Even if I can do it part time, it's will be only 10 hours of focus per week - it is too little.