Crazy is the loud part. The first months, the phone checked too often, the impatience for Friday evening.
The part that keeps it going is quieter and faintly unromantic: who books the dentist, who notices the other one has gone silent, who says sorry first on a Wednesday.
Couples who stay wild about each other for decades tend to be unusually good at that second list. The intensity rides on the back of unglamorous attention. If the loud version is not in the room today, check whether the quiet one is.