My ex-wife, Natalie, and I had an amicable but not loving marriage. We had 2 children, Michael (28M) and Lily (30F).
When Michael was about 10 years old, she and I saw that we no longer had romantic feelings, but a beautiful friendship. But for reasons at the time (mainly our children), we decided to continue the marriage until our children left home.
Basically nothing has changed on a daily basis, we were still the same couple as always, but we didn't force something we didn't want. When Michael moved away for college and home permanently (at age 19) we decided to make the gradual move and finally make our divorce official.
Michael didn't handle it well. For months he tried to convince us to try couples therapy, "intervention", that it was a bad phase in the marriage and not to sign the divorce paper until we were sure.