Really? I have always taken this to mean that ONLY fornication (as George has so defined it) would be a reason to "put aside one's wife". In other words, the only basis for a marriage ending (or being recognized as dead) is adultery.
We can think also why fornication is defined as the single reason for divorce.
In my opinion, sexual intercourse with another person signifies in the most certain or obvious way that the couple is practically already separated, it proves that they don't love each other enough to keep even this basic element of the exclusivity of their relationship.
If this reading is correct, then fornication is just a characteristic case, it shows that a marriage should be formally ended only when it is essentially ended. For example, if your spouse gets easily ungry, this doesn't prove necessarily a deep separation.
I believe that we should not read the advice as if it was a court law, but to understand its spirit, to discover the whole field of references in the life of a couple that would explain their essential separation and justify it even formally. The advice means, if I understand it well, that a couple may get a divorce if at least one of them doesn't love the other, and only then.
I do not disagree, George. What I did post was my understanding of what is accepted in the venue of an Ecclesiastic Court for Permission to Remarry, which I guess by definition is a legalistic application.
Is this what happens in the US? Because in Greece, so far as I know, fornication is not the only case when the Church accepts the divorce of a couple. Practically, it is enough for (any of) them to just want a divorce, and a divorce is granted.