She was in a volatile relationship it seems before me, and as far as I can tell the sex was great with this guy - and that’s what she’s comparing me to. Fair enough, but she admitted herself that the only reason she could be kinky with this guy is because of the volatility and love/hate relationship they had. In other words, it felt good to be dominated by him, and sometimes dominate him.

I honestly think this says it all right here. You will never be able to fulfill her in this way considering the volatility of the previous relationship. She needs to go to therapy to sort this out because this isn't you OP. This is definitely her problem that she needs to work out with a decent amount of therapy.