(I personally know two formerly "decidedly" gay men who have been happily married to women for years.
I've known gay men who were married to women also and they're still gay, always were and will likely be gay always. One's marital status has little to do with orientation. One may wish to live a so called Normal life and could go through all the steps necessary to achieve that but one can't wish away one's natural orientation.
Think honestly for a minute and think through how you might try to change your heterosexual orientation in your own mind. Very unlikely you could I would think. Those that say they have were most likely not gay in the first place and/or were bi-sexual or emotionally screwed up.
Your argument is valid IF you completely accept the premise of "sexual orientation" to begin with, especially in a purely organic sense and not caused by external factors such as an environment, etc., AND if you do not believe in the orthodox scriptural view of homosexual behavior as sinful. "How can what I'm doing be a sin," one could argue, "if it is my natural state of being, something that God placed in me to begin with? The Bible must be wrong on that point." You either have to accept the Biblical perspective or explain it away, as liberal theologians do, as a function of culture or antiquated ignorance.