The old couple holding hands in the restaurant were your age once, making the same choices. That’s where it starts.

Forty years of anything has to begin somewhere, usually in unremarkable decisions made by people with no idea they were starting something. Nobody arrives at a long life together. They accumulate it out of ordinary weeks and a lot of quiet repair work.

Look at the habits inside your friendships and at how you treat the people you like. Those are the raw material, not some grand decision waiting for you later.