I have just deleted something on another thread because it was moving miles away from the OP, but am interested to know.
I have no problem with couples who are not monogomous. I do, however, take issue where one person cheats because they would not mind if their partner did too, but doesn't tell the partner that they are sleeping with someone else. Personal views on cheating aside, if you don't think monogomy is necessary for a happy relationship, why would you not tell your partner? It must be because you think you are doing something wrong, something your partner may not be entirely happy with. Why would you happily shag lots of people without giving your partner the same option, if it does indeed make for a happier relationship? I think it is the deceit that makes me uncomfortable, but I know some people who have cheated on their partner and claim that it has made them a better partner, more relaxed, less needy etc. So tell your partner, let them sleep with someone else and then they can see if it improves the relationship for them.
AIBU to think that monogomy or the lack of should be an agreed thing in a relationship?