A couple of thoughts from when I FIREd a few years ago.
(1) Having a super definitive and clear conversation in advance of retiring or semi-retiring is REALLY important -- This step helped me and my partner bring up concerns and figure out how to tackle them. In fact, for each serious concern, we defined the specific steps we would take to address (almost like a formal risk management plan).
(2) Having a budget is everything -- Prior to my retiring, we had no detailed budget. We had designated portions of our income to household needs, mortgage, to retirement accounts, to non-taxable investment accounts. As part of planning for my retirement, we did a specific and detailed budget. Running our household a bit like a business with an eye to long-range planning acts like a framework for collaborative decision-making. Most of our discussions and decisions involve shifting spend from one area to another based on what we value the most, but staying at the agreed-upon spend level.
(3) I retain the flexibility to change my mind -- Having experienced the sheer joy of an early morning spent gardening while my dog sleeps in the sun, free time with my partner or an afternoon working as volunteer coach, I doubt I'll change my path. But, I continue to learn to be flexible. if parts of my situation or my family situation changes, I can start a business, consult a little, get a job, etc. if that's what I need to have a life I value.