Feeling raw after sex

My partner has expressed feeling some discomfort sometimes during and after sex. He described it as a raw burning feeling. We tried using lube and he still experienced it. I don’t feel the same sensation. There are no STIs in the picture and the only thing I could think of is me having a tilted uterus and vaginal canal? He joked and said he thinks I’m too tight. Can my anatomy actually be an issue? He’s said he’s never experienced this with any other partners. Has anyone had this problem? I think we will try a different lube too. The sex is enjoyable for both of us but it has caused him to have trouble finishing due to the discomfort. Our sex drive is pretty high soooo I’m thinking it could also be the frequency of our intercourse. Give me some tips!!