Sexual orientation is not a choice. No human has any say over who they are attracted to and who they develop romantic feelings for.
If gay people could choose not to be gay... many of them would because it would make their lives so much easier. While a gay person can choose to deny their feelings and live a life of solitude, or lie to someone of the opposite sex and enter into a sham relationship with them just to fit in, they are still gay whether or not they engage in same-sex relations. That's not a choice about being gay or not though, just a choice about acting on your feelings or denying them and being miserable.
When the choice comes down to:
Living a lie and being unhappy and unfulfilled because you aren't with someone you truly want to be with...
or
Being honest with yourself and those around you, and finding someone like yourself who wants to be with you as much as you want to be with them...
what would you choose?