Tigris, are your feelings strange? No, not at all. My wife is going thru almost the exact same thing. I understand your need is very strong and understanding the reason may not help lesson it. Speaking from some experience here, if you're in a happy marriage of 17 years, your husband loves you and is willing to do most anything to make you happy. On top of that, the fantasy of your wife with another woman is very exciting but when the fantasy threatens to become reality or actually does become reality, it can be very detrimental to a long-standing, successful, monogamous marriage. Hurt feelings, jealousy, insecurity, feelings of betrayal, can develop. In general, these things usually do not work out well for marriages. So, I can't say it will be easy but my advise would be to try to fulfill your desires with fantasies. A real physical relationship outside your marriage risks harming the foundation of what may be one of the most stable and supportive parts of your life.