When he wants you to come first, YOU have to do something to make that happen?
That's HIS job!!!!
I think he's putting all the responsibility of doing it the way he wants, on you. That could be stressing you so that you just shut down.
I never felt it was my wife's job to make herself come first. When I figured out that the only way she would get to come during sex was for her to come first because if I put it in first I would come too soon, I figured it was MY job to make her come, not hers. For me that's the best part of sex, me making her come. That's the best satisfaction I can have.
By the time I was through, she was plenty wet.