I cannot even imagine how things are for you. I've never been abused, at least not sexually. When I hear stories like this I just see red and would like to see justice done.
The only thing I can address is the medication issue. Personally I am so very grateful that I live in an age where these medications are discovered and available. I would not be able to cope very well without them. Taking them changes my life radically. Since I consider my depression and anxiety illnesses, it doesn't trouble me to take medication over the long term. I hope you can come to see your meds as a wonderful tool to help you live your life. There is nothing shameful in using them.
In my opinion your fiance' needs to be told everything. He needs to have a chance to process everything you tell him before the marriage. If you need help maybe one of your drs. can work with you in telling him. This is a part of you. He needs to know.
Also--- if this person who assaulted you is still a part of your life then the people you mix with should be informed about him. That may be all the revenge and closure you need. Shame him in public and watch him wither. As I said--- just my opinion.
I hope you feel safe here. Post whenever you want to. We are here to listen.