Hmm, not sure your therapist was very realistic. I am fortunate, I have never felt disgusted by my sexual preference. For me Its about control or lack of it it.
I suppose I just wanted you to know your not alone. These feelings can be overwhelming in your teenage years and early 20's. They will settle into something more manageable as you mature and experience more relationships.
Stay positive,don't beat yourself up, not all these things are triggered by trauma. Sexual preference is as varied as people's taste in music.
I hope you can find a comfortable place to be yourself.
All the best