As a 40+ single woman I frequently get the same issues. But now that I think about it, I’ve encountered this with all sorts of couples including AA ones. It makes me wonder why you think it’s only white women. Many are paranoid that if their relationship isn't perfect this week then their man will stray and attractive single women are the enemy. What's funny is that the guy being part of a nice couple is often part of the charm and if he breaks that, any human interest in him is usually gone.