Dude, sex is hella important to me. I'd definitely divorce someone that I wasn't sexually compatible with, especially if I couldn't have sex with anyone else, but then I wouldn't have married them to begin with.
Unless your husband "doms up", which you said comes across phoney, you won't be satisfied by him. You just aren't sexually compatible. Only you can decide whether you are willing to sacrifice good sex in order to stay in the marriage. As I've already said, I couldn't. I need to have fulfilling sex with all my partners. You aren't saying that you care more about C's penis, you are saying that you have to meet your sexual needs which isn't unreasonable.