Cambodian wedding

Depends on how you feel about being nice to your new relatives. Of course they will want you to accept their traditions, but it's not compulsory.  Just do what you feel is comfortable.

"When in Rome, do as the Roman's do". Best I can offer to your question.

@Georrges Simon

Hi when you marry a foreigner east or west, to not don the traditional dress if required is like telling your bride she can't ware a white wedding dress, a male mostly wares a monkey suit of various types, but this is Cambodia it has long very old traditions and must have respect for parents, you have a choice but your intended partner will expect you to integrate with Khmer life, a starting point is getting married, and respecting the parents, what you do is your choice, but it should really be a joint decision between you and your intended you could cause her deep embarrassment if you where not to ware traditional marriage attire.