I think what hairdog is asking you is: has she seen a doctor about these ailments?
That would be my first condition upon re-entering the marital home. The second one would be a sex therapist. Under no circumstances do I believe you should go back because of guilt--after all, she doesn't seem to be feeling one lick of guilt over abandoning her position as your wife.
There are legitimate claims towards pain during sex and most of these have been shown to be psychological in nature. As far as her feeling that her insides are being ground to bits, well, if she is laying there thinking that she hates having sex and she is so resentful of you for forcing her to do this...I mean, can you see how a person can start to focus on the sensations and give them a negative connotation, when they are doing something they don't want to do?
Most of the advice you will get here is to be compassionate and loving but to stand your ground. There is no reason to be hateful to her but you must treat her as an adult and stop accepting her inaction (in regards to her pain) as a legitimate course of action.
