Have you ever wonder that after broke up or divorce, the quantity of love making tend to increase or decrease? I think it depends a lot on the person's character and situation, right? If the one whom broke up, feels sorrow and hurt, do they have the mood to have sex? They may feel bad and look for some new excitement to forget the past, they may even feel hurt that feel like want to revenge to their ex by having more sex after broke up. But I always feel that when people are hurt, they may hang out more, this will give them more chance to explore the world outside.
Well, I always believe that there are no one in the world that can't be replaced unless you are Brad Pitt or David Beckham. Revenge sex is a common thing in life as well, you don't want me or long to have sex with me then there are a bunch of guys/girls who enjoy my body. Not sure that it is a mature thing to do but the moment that you enjoy the sex, you are in heaven. If you are faithful while you are in a relationship, then you maybe very happy as you have the chance to make love to whole lot more of different people.
Some of them out there have evolved from a very good boy or girl to a playboy or playgirl. Since there are not many of them who appreciate what they did, it's no surprise people tend to choose to have casual sex. It's not easy to have a good relationship, it depends a lot not on one of them but both parties. There are far too much variables that will affect a relationship.