Here is the reality. If a guy has an attractive wife who enjoys sex, she is going to go out on him. It's simple biology, and all this marriage vow, love and cherish, blah blah blah, is a lot of clap trap. So a guy has choices, leave her and find an unattractive woman who no one would be interested in, drive himself nuts by fretting about it, or have an open relationship...let her go with whoever she wants within reason, no friends or co-workers and whatever parameters you can agree with her on. And this is not limited to women with white husbands.