@Yui ************
, something you might do is stop by your local amphur and see what you need to do to get your marriage from overseas registered here in thailand.
When people get married here they get two marriage certificates called a Kor Ror 2 and a Kor Ror 3 (คร.๒ คร.๓) BUT when a thai is married abroad and registers the marriage here in thailand they get a Kor Ror 22 (คร.๒๒).
Unless I'm mistaken once you have the marriage registered at your Amphur you don't need to show the translations and certification from the MFA anymore.
The down side is in order to register the marriage at the Amphur you need to get the marriage documents translated into thai and certified by the MFA anyway :/