I am not Asian, but wife is. Took years, literally, to persuade her. Keep in mind she was raised in a very conservative culture and was a virgin until I came along.
We started by watching porn together. She was especially excited by gangbangs, her pussy would get soaking wet. I would say to her things like imagine how much fun you would have if that were you. I bought her a vibrator and she found she really loved the sensations and we gave it a dude's name. I would say to her I am sharing you with...etc. She would get even wetter and cum hard, several times a session!! We also engaged in role play, where she was a ***** and I her client. Also, roles in that I was someone else.
After several years of this I told her I would like to set up a real threesome for her. She was not sure I was serious at first. I also had to reassure her it was not adultery, since I would not only I be consenting but also be present and a participant as well. She was concerned about jealously issues, she knowing that I feel jealously is poison to a relationship, that took a bit of persuasion. All in all, after about six or seven years she told she was ready to give it a try. We set down of rules and found someone suitable. The rest has just been great fun!! I always take video of our threesomes, because we like to watch them together. Lovely way to spend an evening with your sweetheart!! Hope this helps.