All Pain Originates as Fear...
Beliefs, thought systems, core biases: these are the culprits for all our emotional pain. We cannot experience this type of suffering without first believing there is something to suffer about.
For example in a relationship between lover, monogamous or not, the other person has the right to cheat on you. (Shocked me, too.)
You have the right to believe many things and you will then, throughout your lifetime, make decisions based on said beliefs. If you have been 'cheated on' you have the right to believe society and the movies and your BFF and all the people who propagate that this is the worst thing ever. If you choose to believe that, you then have the choice to remove yourself from the "cheating party". This maintains your responsibility of self versus perpetuating the assumption that when 'wronged' you have the right to 'punish'.
Often, we're inspired to believe that "love" gives us the right to "demand" when in fact "to demand" is the exact antithesis of "love". No one has the right to require another person to do anything, wronged or not. We only have the right to adjust ourselves based on the situation.
Three choices make life much simpler when facing one of life's many obstacles:
accept it: meaning - "I will allow no resistance. This happened. It is. Now, I will move forward."
change it: meaning - "What about me can I alter to be the change this situation needs to become better, fore I know when I change the things around me begin to change too."
walk away from it: this is the last resort, typically. You have tried to change it, but during changing you have noticed too much resistance (causes toxicity, both emotionally and physically) which means you are incapable of even temporary acceptance, so now, you remove yourself.
This is not an indefinite decision, as I find there really are no indefinites. Things are always changing and sometimes we have to step away in order to come back renewed.
(written with love - spread the light)