My wife is Philippina too. The swinging lifestyle has always interested me and I explained to her what it was about and made the focus be on her.
She then acted interested and we met a few couples from a lifestyle site. From our first encounter, she has been fully on board and is very active. I had some of your same feelings about sharing her, but when it happens, it just intensifies our love for each other. I could not be more proud of her.
Her initial fear was that family or vanilla friends would find out. We have had a few discover, but as it turns out, they are curious and want to know more. So, we have fun filling them in on the activity.
Bottom line, just be reassuring to her that you are not doing it for any reason other than you are proud of her and want to to have a great time. If she is having fun, she will appreciate you for having the trust and faith in her.