Have you run your numbers including your future SS in a retirement calculator, like the Fidelity retirement income planner? We did something very similar and ran all our income sources with and without the business income, and with the business income tapering off, in various calculators, plus made our own spreadsheet. My Fido year by year cash flow detail is my financial security blanket. It feels weird not to have to work full time and not have DH's steady megacorp pay check, especially when most of our friends and former co-workers our age are still working or laid off and looking for work. I have to keep referring to cash flow report to know we're fine.
At first glace, it looks like a great opportunity to downshift. Who knows, you could end up making more than your current job, plus you would have the business expenses to help manage taxes and you are investing in another business you might be able to sell in the future to help fund your eventual full retirement. You can sell a business but you usually can't sell a job.
A couple of books to help you decide are Plentitude by Juliet Schor (also author of The Overworked American) and What Happy People Know by a Canyon Ranch director who works with highly paid, stressed out executives.
