that is the USA, not Thailand. This is a Thailand visa advise page, unfortunately most people here wouldn’t care less if you used red ink in the USA, not meaning to be rude of course, this is about what you use in Thailand.
actually the TM30 has always been part of the immigration act of 1979, while it wasn’t always enforced that much years ago, it is pretty much enforced nowadays, it’s not hard to do.
The TM30 has not been scrapped, you are probably getting confused with the TM6 arrival/departure card. Also there is no such thing as a common law wife. If you are legally married in Thailand your marriage will be registered at the local amphur office and you will have a marriage certificate with a rose border around it, if you don’t have you are definitely not married here.