technically that is the line that the people supporting the greatest number of dick in a given pussy (or reversed) defend. I just don't get why it couldn't be possible to progress in the practice of love with the person that really loves you and vice versa... I don't see how having intercourses with others people will permits you to gain any form of experiences or conducting experiences that may improve your relationship with the person you love. The problem of this approach of Kleenex-sexualization is that you don't want to accept that you need one life time to be the master of the body of your partner. Don't forget we don't have the same standard for mastering before you answer.
To take an airplane imagery, it's not on flying on multiple plans that you will become master of your warplane... only those that can understand will, the others will diverge, until they get it... I told you so, here.