If sex is the only thing that matters in a relationship, then they are all doomed.
And if you read the numbers for people who have 'affairs' in 'normal' relationships, you might as well fuck the bridesmaid on your wedding night because your bride probably blew the best man on the ride to the Church!
But given that we have such strong moralizing over 'sex', it does take a certain 'whatever' for a woman to cross that line and become a prostitute -- and the encounters that she will have with men will not all be good and great and awesome and there may be some issues there or not.
The bottom line though is if the only thing that matters in your relationship with women is 'who's she fucking?' then you will be miserable even if you marry a virgin! There has to be more to it than that ... and anyone can make the decision to have a monogamous relationship or not: accidents don't happen when it comes to sex, she either says 'yes' or its rape.
It is, however, up to each person to decide what they want in a relationship or not ... you can't go into one to rescue someone or change them (take note ladies!!!) and expect happiness. If I'm a happy ball-scratching flatulator going in, that's just going to be part of my charm for the duration.