First, I have a long time friend that was sexually molested by her stepfather for 5 years. As an adult she has slept with way too many men that have used her and she thinks she is just enjoying herself. Really, what she is doing is acting out, as the same with your gay friend. It is called SEXUAL ADDICTION! This is not particular to gays! It is called a process addiction.
Now, my whole point is that this is NOT about CORRECTNESS! That is something religious doctrine tries to influence and control, but is fast losing the battle due to the other negative forces at play.