I believe the same thing too that homosexual mostly is psychological disorder. That's why I hope there is therapy that can make them have desire to opposite gender too, so they will be able to choose heterosexual way of life. I think like this because I found there are many bisexual in my place who choose to focus their desire only to opposite gender and avoid homosexual activities.
No it is not "too"..Bisexuality has the homosexuality as well. The homosexual activity comes from the homosexual thought and the homosexual thought (If it doesnt originate from a biological disorder) is an abnormality and can be corrected through some therapy. So it is not that one can have homosexual desire but can live a marriage life with his/her opposite gender spouse at the same time. This may cause a problem in time.