My situation isn't quite the same, but it is leaving a well paid job when I have two kids and a mortgage in order to work in some to-be-determined field where I have no experience, with no opportunity (after a short window) to return to my former field if I change my mind.

First, have some savings and a plan to minimize burn rate if things get tough. More importantly, there needs to be a compelling answer to what you're accomplishing for your family, or what you as a family are accomplishing, by making the change away from your present comfortable arrangement.