Hi. I Need Help With My Issue Of Lack Of

Hi. I need help with my issue of lack of libido. I'm 24 years old and do not feel the desire to have sex. I do not think I have ever experienced an orgasm. I have been on antidepressants since 18 years of age and before I had my first sexual encounter. My psychiatrist has decided to slowly drop my dosage because of these issues but as such I have not experienced any difference sexually. I have never masturbated before nor felt the need to. Recently I have attempted masturbation in an attempt to help my relationship but I simply do not find any excitement in it. If I do not sort out the issues soon my boyfriend of 2 years will leave me. He has tried everything to get me excited about sex but it just does not work. He can also tell that I'm faking. My ex boyfriend before him left me because of the same issues. Please advise