Does not need one, just police clearance (finger print taken at the police station opp central world and mail it back to your country's police dept handling police clearance.) and a 'Affirmation of Marital Status' from your own country. They need to be stamped by your embassy and translated to thai, than stamped by MFA in bkk. There is a translation shop at the 2nd floor of MFA. (passport needs to be included as well) (bring your half to the khet and ask them what is needed.)
Go to the thai embassy in your country to apply for a retirement visa, use that to come in bkk, and use that to open a bank account. go google, not that hard.