The owner suggests that it is a safe alternative for what he would coin as natural behavior (i.e. cheating). His argument is that monogamy is unnatural and folks will stray and its better to stray with folks that are not looking for drama and have been screened.
I come from the school of thought that if an adult wants to do something, they will. However, I am truly concerned that a website/service such as this will only make it easier for married folks to cheat.