You have been dealing with touch issues for 15 years, you have not been able to directly discuss your issues with sensei, friends, nor family for all that time, and you feel that you have to resolve some of these issues in the next couple years so that you can improve in aikido?
I really think therapy would be a huge benefit. You are admittedly carrying a huge load of shame and self-judgement. Therapy can help you re-evaluate and reframe your experience. Therapy can give you strategies for rebuilding trust, rebuilding confidence in functional boundaries, and managing recurring stress. Aikido can work in remarkable harmony with therapy to help resolve your issues.
Find a reputable therapist who specializes in assault and rape recovery. Psychology Today magazine has an online listing of therapists, it is reliable and good. Vet your therapist carefully, and not around martial arts knowledge or experience. Aikido is not the issue, your unresolved feelings about your experience are the issue.
Well, it has been almost 15 years, this isn't something new that I have been dealing with.