This is not about guts (courage). Unless a woman is very secure and has a big understanding of the difference between s3x and love (or is in a polygamous marrriage), this question is about having your cake and eating it too. Few marriages can survive this, and certainly not if they would base the issue on "guts". Now, having cleared that up, my husband has permission; if he wants to be with somebody else, that's okay. You can't make somebody want you. I don't particularly need to know the details, either, and I would if I wanted to, also. No diseases please. Monogamy tends to be a western ideal, and a moralistic one, at that. But I don't believe in polyamory, myself. These issues have to be tested for commitment-phobia and to know if one person has one foot out the relationship door already.
Im praying my soon to be ex will do just that. Its someone elses turn to be dissapointed and pissed off.