Does a multiple re-entry stamp remain valid when extending a spouse visa in Thailand?

IF you have a year "extension of stay" based on marriage to a thai that you got from the immigration office here AND a multiple re-entry permit when you get the new year extension you need to BUY a new re-entry permit

remember though marriage visas get a 30 day under consideration stamp when you apply for a new year extension

DO NOT buy the re-entry permit then because it will only be good for those 30 days, wait until you go back to get the year extension inked in to buy one and it will be good for the whole year the extension is valid for