Most men are not able to feel the diaphragm. Some men may feel it during intercourse, but it shouldn’t be uncomfortable for either of you if this is the case.
Women usually don’t feel the diaphragm inside of them if it’s inserted correctly.
Some women do get urinary tract infections from using the diaphragm. It might help if you pee before inserting the diaphragm and after you have sex. You might also check with your doctor to make sure your diaphragm fits correctly.