I'm sick and tired of most Asian LGBT series or movie ending like sh*t.
First, there is not such thing as liking someone that identifies with your same sex and not being gay.
Second, most certainly not every gay has a girlfriend/boyfriend, and most definitely not every one in the exact same period of time that they realize they like their best friend, coworker or else.
Third, you can choose to be with the person you love and have a happy ending (I know there are a few dramas that end well but it's the minority).
Fourth, you can break up with the person you are dating before you act on your desires.
Fifth, if you don't want to be with someone, or you start having feelings for someone else while in a relationship you should break up with the person you are with, you don't have to wait till that person cheats, or gives you a reason, not wanting to be in a relationship is reason enough.
Last but not least: BEING GAY IS NOT A BAD THING, IS NOT A LIFE SENTENCE, OR SOMETHING TO HATE YOURSELF FOR, IS JUST LIKE YOUR TYPE OF BLOOD, OR YOUR ZODIAC SIGN, IS JUST ANOTHER FEATURE ABOUT YOU THAT'S ALL.