Long separations are common and they do not create a special obstacle. New York has no automatic divorce after a period apart, so the marriage is still legally in place until a court ends it.
Time apart is not a divorce
People are often surprised by this. Years of no contact, separate homes and separate lives do not dissolve a marriage on their own. Until a judgment is signed and entered, you are married, with everything that carries for property, inheritance and remarriage.
It can help the filing
The no-fault ground requires the relationship to have been broken down irretrievably for at least six months. A separation measured in years clears that comfortably.
The real question is usually where they are
After a long gap the practical problem is locating the person to serve them. If you genuinely cannot, the court has a process for that.
This page is general information about how the process works in New York. It is not legal advice and it does not create an attorney-client relationship. Whether any of it applies to you depends on your situation, which is what a consultation is for.