For Thailand you always need a certificate of marriage for anything to do with a spouse. No jumping over a broom stick in a Buddhist country. I think you are talking about a common law wife/husband. No!
Before DTV they had ED visa's so people who pay a school to enroll on a course so people could get a visa and not attend. So imm started making checks, people's visa's where cancelled and they were given 2 days' notice to leave. If you are planning to do the same for 5 years, good luck.