Obviously, when coitus stops, you are in trouble. If it continues for more than a year, I am told there is a legal name for it – Constructive Abandonment. Coitus cannot stop in a marriage without consequence.
But why does it sometimes stop? What caused a couple to grow tired and bored with each other? Is it a function of time? Is it because you are married too long? At my age I cannot imagine being married to the same person for more than, say, a decade. And having coitus only with that one person all these years (fidelity). I believe in fidelity but I am not sure if it is possible eternally. I have never personally had the same boyfriend more than five years. Of course, I have only had one boyfriend so far and I am 22.
With that said, the cessation of coitus in a marriage seems like it would be a big problem and a cause for divorce.
Can you tell me why you stopped having coitus with your spouse in the comments below so that I can give you my unsolicited advice?