Jan Fawcett, MD
Thanks for your question. I would suggest starting psychotherapy as soon as possible. Sexual abuse can leave profound emotional scars. I want to assure you that it is not your fault. You deserve to live a full and happy life, it is up to you to get the help you need. Hopefully, your spouse will be supportive of you and might even agree to go to marriage counseling if you decided that is necessary besides the personal psychotherapy.
Yvonne Hall, MD
Through therapy, you will be able to achieve inner peace and a healing perspective on the traumatic event and on your own strength and abilities to cope so that you can move on with your life and not feel "haunted" by the memory of the trauma.
I think that you should meet with your Fiancé' more than once and talk about different things to get comfortable and then tell him about the past unfortunate experience as well as the level of your comfort in terms of getting intimate after marriage. If you don't feel comfortable doing it on your own, you may want to get help from a professional counselor who can facilitate meeting between both of you.
Nonetheless, I believe that it is necessary that "genie" is out before marriage so it doesn't cause any complications afterwards.
Sometimes, Antidepressant/Antianxiety medication could also be useful during the facilitation process.
Hope it will be of some help to you. I fully understand your situation and empathize with you and wish that I could help more than that.
It would also be beneficial if you and your future spouse were involved in couple’s therapy. This could facilitate communication, and help provide education to your future husband regarding the initial difficulties related to intimacy.
There are medications which might also be helpful initially to reduce anxiety and intrusive thoughts. These are sometimes beneficial early in treatment, but the mainstay will be the work that you do in psychotherapy.
I wish you much success.