What visa can the spouse of a retirement visa holder apply for if she is under 50 years old?

@Benj****

gave the correct answer. One person applies for either a Non-O-A (long stay) or a Non-O visa based on retirement and the spouse applies for a 90 day Non-O visa based on marriage to a foreigner on a 'retirement visa'

That's the way it's done all the time for "trailing spouse" AND you have to get that visa from a thai consulate outside the country because no immigration office will issue an in country 90 day Non-O based on being married to someone on a retirement visa. It's not a valid reason to get a Non-O issued in country.

That would be a Non-O visa based on being a trailing spouse