Having many partners like this causes mental and spiritual damage by making it extremely difficult for you to have a successful and happy monogamous relationship in the future. This damage can carry between lifetimes and be very difficult to heal from. And in future lifetimes, it may be impossible for you to find a partner who you can live a happy life with.
We have free will. There is really no "allowed" or "disallowed." You are equally allowed to stick your finger in an electrical socket, or to put your hand into a fire. If you choose to do something like that, nobody will reach out and prevent you from harming yourself. And you absolutely have the "freedom" to hurt yourself with a stupid action.
But the gods do not want to see us harming ourselves. They want to see us growing and improving and healing. If you choose to harm yourself, it is just disappointing because you could have made a different choice that would leave you to having a better and happier life, and for all of your future lifetimes to be exponentially better and greater than the current life.
Most of the greatest and most important things in life take hard work and discomfort to build and create, and may take a long time before there is a reward. I am not aware of anything truly great and amazing in the world that can be had with no work, no effort, and just doing what instantly feels good in that moment. Most of the things that feel good in that exact moment are the things that are most harmful, like using drugs or eating too much unhealthy food. Going for instant gratification and gluttony is just trading a small instant drop of dopamine in exchange for hurting yourself and directly making your life worse, in most cases.