I think checking for any infection is a good first step.
There are some dermatological conditions that can sometimes make the tissue more friable, the most common is called Lichen Sclerosis, so I would ask your gynecologist to rule that out.
I am not sure if you are on birth control pills, but that can make the tissue at the vaginal entrance more friable as well in some women. If you are on birth control, sometimes using a local hormone cream applied to the vaginal entrance regularly can be helpful.
I would make sure you are using a really good lubricant, maybe try a hybrid lubricant or a silicone lubricant, to reduce friction.