I'd like to hear in the long term how you two and your bull all evolve relationship wise as well as sexually. If in the coming months this sexual desire your wife has for her bull, eventually loses steam. As we've said sexual fulfillment alone shouldn't be enough to risk your relationship, there are probably many qualities she finds in him annoying and many qualities she really likes in you.
I have read about many women who have left a partner that is sexually great and satisfying but a jerk for one that has many of the qualities that she is looking for, but is not a porn star in bed.
Thinking about it from a man's perspective. I had a girlfriend who had a amazingly sexy body, who was a nice woman, but over the course of years we grew apart to the point where I found her really annoying and we argued and disagreed a lot. In the end even though she still had that same sexy body, I had no interest in having sex with her because I found her so annoying and irritating. Needless to say that we broke up and later I met and married my wife. Even though my wife doesn't necessarily have the really sexy physical body of my ex girlfriend, there's absolutely no comparison of who I want to be married to, you guessed it, my wife, because on so many levels we are connected and are soulmates.
Knocking it out of the park sexually is a itty-bitty part of a relationship, it's nice to have, but it ain't going to save the day.