Her giving “her best” to another man before is irrelevant.
In this context her best meaning some type of sexual act or enthusiasm when it comes to sexual relations as is commonly stated when it comes to this conversation.
It is irrelevant if she was more sexually open or enthusiastic with a previous partner because that’s not the reason you should be upset. You should be upset because you are not getting your wants met. If you wanted to have crazy kinky sex then that should have been something you should already have been discussing or participating in. If when you request a certain act that you want to participate in and she declines. You have 2 options in that situation either accept that you’re not going to get what you want and leave or accept it and truly move on with your relationship.
Any extra knowledge that she did it before should have no bearing on your decision. You can feel hurt, that’s ok but you either leave or get over it purely because you are not getting the act that you want to participate in and not because you need to prove yourself superior to some other random guy.
If the only reason you would be ok with her declining sexual acts that you wanted is because she had never done it before you, then it was never about what you wanted but your need to be “better” than her previous relationships.
Just leave and find the girl that you are fully compatible with, the one that will make you feel fulfilled regardless of what kind of relationship she has with previous partners.