Because I'm not a mind reader and at no point in his post does he say his wife is a citizen of Myanmar. He's asking about a Thai visa to visit his wife in Thailand in a Thai visa advice group. It would seem logical to think his wife was Thai and therefore he could obtain a Non Imm O based on marriage. OBVIOUSLY he cant aquire that visa based on marriage but if he's aged 50 or over he could still obtain the Non Imm O visa.