I think that using all of your life savings to start a business can be very risky...I understand your desire and confidence to do so and I don't want to take that from you, but the whole family needs to be thought of....it can take a good 5 years to see any profit and that can put a tremendous strain on the finances for the whole family. I would continue to discuss it with your wife and ifgure out what will work best for all of you.
I think using some is reasonable but still carries the risk...I am all for entrepreneurship but at the same time, not putting others at risk if it is not clear that you can recoup what you put in and make a living for yourself and your family. Her desiring to separate is based on her wanting to be removed from the stress. She has cared for you and worked while you have been ill and she is feeling the pressure. I hear how serious she is, so I would consider that deeply before you plow ahead.
Please take a moment to click on the rating tab to rate my support. Thanks very much in advance. I wish you great health and success in whatever path is chosen.