@Gerald *******
Okay, then you don't need to get anything other than a year extension of stay either based on marriage (where you need to have the 400K baht in a thai bank account in your name for 2 months before you apply) and a pile of paperwork (marriage certs, wifes documents, etc)
OR
You apply for an extension based on being over 50 (retirement) where you need to have 800K baht in a thai bank account in your name only for 2 months before you apply for the extension, then you keep the 800K baht in the account for 3 months after you get the extension and the balance can't go below 400K the rest of the year.