If it is in her mind you need to deal with it in a nice way.
I am not going to get into all of the graphic stuff when it comes to sex, but I will tell you this.
If your Filipina wife thinks you are having sex, or even thinking of having sex with someone else, you better watch out.
Assuming you are not cheating, you need to find a way to put this to rest or your life will be a living hell until you do. Even if you think her fear is irrational, that makes absolutely no difference.
For me there is something about a petite Filipina lady with that long silky black hair, a golden brown complexion, and a cute accent, that puts me in the mood for sex.