I have firsthand experience with this, and it sucks for both parties. Ex wife's vaginal canal was.. shallow, I guess? Not uncommon. But hitting the cervix is painful. And for me, making sure I DON'T kind of takes a bit of the excitement away.
Not only that, but she had a hyper-sensitive clit, as in painful for her when she was aroused.
AND, she had TMJ, so her jaw would lock if she opened her mouth too wide, for too long. So that took care of that part of sex...
Ironically enough, she had a pretty healthy sex drive, so there wasn't a lack of it. It was just making sure to be careful, use the right positions, and not get carried away (me, anyway)
She also never bothered to see a gyno, or even mentioned anything to her doctor, afaik.🤷♀️
My now-wife has none of those "issues", likes it hard and deep, has multi-orgasms from clitoral stimulation, and her jaw opens wide
But she has 1/10th the sex drive my ex wife did, lol. Can't win 'em all!