back of the mind thoughts of females

I have a question for the ladies. If u r in a relationship or married and u tell ur bf/husband that u would never do anything with another woman do u really mean it or is there still that outside chance that u would but u wont say it? My wife has had several different people females ask to go to different places with them from a place for lunch to a gym and unfortunately my ex calling her her bff. I pick at my wife bout all this but im still curious as to what is in the back of her mind but she wont say. Do any of u have the same situation? My wife to me is an attractive female and it wouldn't surprise me if some female would try to hit on her