After 35, after kids, after years on flat mattresses—women's bodies need different support during intimacy. Specifically, 27-degree pelvic elevation. Without it, you're literally crushing her spine while trying to please her.
She's not rejecting you. She's protecting herself from pain.
Dr. James Morrison, who's counseled over 3,000 couples, puts it bluntly:
"Men are trying to fix their technique when they should be fixing their geometry. It's not about what you're doing—it's about the angle you're doing it at."