In the past and until today, for the most part wealthy Thai women often forgo the official marriage registration for a variety of reasons, in particular because they loose scores of legitimate civil rights. Instead, they prefer to perform a ceremony of traditional Thai wedding. This marriage is taken quite seriously by all concerned, and regarded as a lifelong commitment made by the couple. In the eyes of Buddhist religion, the marriage is recognized and sacred, albeit the fact that in contrast to other religions, a religiously sanctioned marriage is void in Buddhism.
Thai Traditional wedding ceremonies and rituals need not be conducted in the presence of monk and are usually performed at someone’s home. Simply put, there is no such thing as "Buddhist Wedding Ceremony", and if monks are present at the wedding, they are not directly involved. If monks are invited, which is happened quite often, there always should be an odd number: 3, 5, 7 and the maximum could be 9 monks.
According to Buddhist faith, to assure a lifetime of love marriage or what is called "a marriage made in heaven", there is an old Thai ritual of 'Merit Gift' -- a donation to the local wat (Buddhist temple) to perform a wedding blessing ceremony. Even it is not directly related to marriage, a merit-making ceremony would mean alot to the bride-to-be and in turn to her family, to have a gift made in their name by you. It shows that you care about her religious beliefs, value the Thai ways and respect Thai culture.