Thai's don't have a monopoly on this. Vietnamese have this problem too. The qualities you love about her also makes it difficult for her to say no to her family. The problem with her family is that your wife has never said "no" to them before, so they are going to keep asking. Help her be strong and explain to her family why she can't help anymore. She is going to feel guilty and conflicted, but with your love and support, she can stand up to her family. Love is hard to find. Hope you guys make it.