From my experience founding companies, you've gotta commit 100% to it to have any chance of success. That doesn't mean working on an idea in your free time. Consider the fact that someone, or even a funded team of someones, are out there putting in 100% effort to solve the same problem. How are you going to outcompete if you're working on this problem in your spare time (which I imagine is quite limited having a wife and kids)?

You should also consider what success looks like for you. Do you want to start a company to gain creative freedom? Do you want a better lifestyle for your family? Are you prepared to spend the next 7 years on this endeavor? How will you balance the high workload (I'm talking non-stop work for a month at a time) with spending quality time with your family?

You should think through all of these questions, then have an honest conversation about it with your wife, and don't sugar-coat it. She might surprise you.

As far as funding goes... You'll want to put away a fund to pay your salary for at least the first 6 months. Your goal in those first 6 months will be to create a believable story you can sell to investors about your vision. If they like it, you'll be able to raise funds to continue working on it and to deliver that vision.