I also think it's a good idea to give up on trying to microanalyze and find a way to make it good for her, but this caught my eye:

"After all, she mostly just lies there silent and unmoving."

A long time ago I read in some magazine of my sister's, that sex is really good if both participants are (to some extent at least) a little "selfish". Not that one person gets satisfaction at the other's expense, but that each person takes responsibility for their own satisfaction... takes the pressure off the other person. You don't have to guess at what the other person will like, they are guiding things in the way they like, and vice versa.

I like sex but I doubt I'd enjoy it much if I were just lying there silent and unmoving. When/if y'all are ever trying again to have her enjoy sex, she might want to take some initiative in doing things that will bring her pleasure. I'm not sure why it's all up to you. You've certainly put forth the effort. Not your fault if she's bound* and determined to not enjoy it.

*No pun intended!!! lol