Hi, It's Dr. C. Board certified Ob-gyne. I can help you today.
I'm very sorry to hear about your situation. I'm also hopeful that with proper treatment, you'll be able to have good sex again.
In such situations, using both vaginal estrogen along with working with a physical therapist who specializes in treating such conditions can give very satisfactory results. The physical therapist uses biofeedback techniques to strengthen the damaged muscles, improve blood flow and hopefully get the nerves functioning again. . At the same time, very slow and gentle treatment with vaginal dilators is also done. I've referred many women for such combination treatment with good results. Most cities have physical therapists that do specialize in this. Home treatment is also possible. Starting with making sure that adequate estrogen has gotten the tissue to as healthy a level as possible. Usually the dosing would be 14 days of daily treatment of estrogen cream 1 gm or Vagifem pellets 10mcg. Then using 2-3 times weekly. After making sure the 2 week course is completed, starting from scratch to undo the association of sex with pain by not engaging in any vaginal penetration at all. But also making sure to have intimacy of all other types, holding each other with masturbation, oral sex, lots of foreplay but NO vaginal penetration. Once the body fear of associating intimacy with pain has subsided, starting with one finger penetration with lots of lubrication and foreplay. This needs to be accomplished for a solid 6-10 times painlessly before proceeding further. Sometimes we also prescribe a topical anesthetic to be used ahead of time to improve chances of success, although I prefer to try to go without. Sometimes it is necessary though. Next comes 2 finger penetration, again lots of foreplay and lubrication. . At no point should a woman "tolerate" pain since that will make the association of sex with pain stronger. Only if 2 finger penetration is successful can penile penetration be attempted. A physical therapist can be very helpful in this kind of retraining as well.
In rare situations, if the vagina cannot stretch enough, surgery can be performed to rebuild some length. This type of surgery is very specialized and must be done by a doctor specifically trained.
I hope this information has given you some hope. Please reply if I can clarify anything or add details.