42 is a lot for anybody (even without considering the time frame), whatever bullshit 'sexual freedom' people wants to spew to make themselves feel better, or want to deflect it by claiming 'you'd be high fiving a guy' (a form of whataboutism). It is objectively a large number when looking at averages. There is no good or bad, perse, although with high numbers it comes with the connotations associated with promiscuity.

Open relationships aren't meant to be a free for all fuck fest, they are meant so people can have an emotional connection with a person while having the freedom to have sex with others. It is supposed to be done to strengthen the existing relationship. Having rules is normal, but something that should have been discussed at the beginning. Changing rules is also normal, and needed because people change with time, although the ones that he proposed seem ridiculous and unfair.

I find it really hard to believe that you have a strong relationship with your fiance, much less care about the relationship, if you have the time to desire to be intimate with that many different people. It seems like you discovered a part of yourself you didn't know existed, and you don't want to admit that you enjoy that part of you more than the one in a relationship.

I don't know if you relationship is beyond repair, its difficult to tell with only one side of the story, but what I can tell you is they your fiance feels betrayed. It doesn't matter who is to blame, because I think you both are, and maybe you just need to talk to a therapist or something.