Orientation is not a choice, and is orthogonal to identification.
I believe that same-sex relationships can be as profoundly fulfilling, enriching, and pro-social as heterosexual relationships.
That marrying a straight woman with a gay man is profoundly unfulfilling for both.
And that denying a class of people something so profound, freely enjoyed by everyone else, and which does not harm anyone else, can indeed be seen as inhumane.
I don't believe for a second any person has this immutable orientation, straight or gay. And likewise, I don't believe it is inhumane for a person to avoid a relationship that is illegitimate. Trying to argue otherwise is like arguing the color blue can also be seen as red.
Have you felt strong attraction for both sexes? If not, have you tried to?