I understand you might not be OK with it, but I strongly believe a person's "sexuality" is innate, just like their natural hair or eye color. For me anything that is innate to a person as unique individual is not wrongbad. It just is.
People will argue about the morality of sexual perferences and behavior, and adopt beliefs that they feel are right for them. To me what two consenting adults do in the privacy of their bedroom (and doesn't involve children in adult sexual activities), is not morally wrong. I've know very conserative couples who firmly beleive sex between a man and woman should be in the missonary position only, and point to the bible as to why they feel other sexual activities are morally wrong. For them, that is what works, and I am OK with that, for them, but not everyone else.