Outside of the traditional, formal "Mr. & Mrs. John Doe", the wife's name is ALWAYS first when using first names: "Jane and John Doe". In social importance, the woman is always first, then males, then children. Traditionally, the man's first and surnames are never separated. The confused idea of the man's name first (John and Jane Doe or Mr. John Doe and Ms. Jane Smith) is neither traditional nor appropriate. At Emilypost.com, she notes that traditionally, a man's name was first on an envelope adddress (Mr. and Mrs. John Doe), and his first and surname were not separated (Jane and John Doe), but that "nowadays", the order was irrelevant.
Miss Manners' Guide to Excruciatingly Correct Behavior and Crane's Blue Book of Social Stationery either state outright or give examples consistent with the following:
Married Couples- formally- Mr. & Mrs. John Doe; informally- Jane and John Doe
In which woman kept maiden name- Ms. Jane Smith and Mr. John Doe
In which man is a doctor- Dr. & Mrs. John Doe
In which woman is a doctor- Mr. and Mrs. John Doe or Dr. Jane Doe and Mr. John Doe
In which both spouses are doctors -Dr. and Mrs. John Doe, or The Doctors Doe, or Dr. Jane Doe and Dr. John Doe