Illustrative example
Someone who married overseas moved to New York eighteen months ago for a job. Their spouse has never lived in the United States, and the marriage came apart after the move.
None of the one-year routes fits: they did not marry here, never resided here as spouses, and the cause did not arise here. That leaves route (5), two continuous years of residence by either party with no other connection needed. So whether New York will hear the case at all turns on a count of months, not on the merits of anything.
They agree not to file for the moment and to use the interval to settle the practical questions - where the shipped belongings go and how the shared account is divided - so that whenever a filing happens there is far less left in dispute.