I want to make him to think that I am happy

I have a best friend who I have a crush on. But now it's not just a crush, I love him. But now he has a girlfriend who I can't seem to dislike. She I'd really sweet and pretty but I can't watch them when they cuddle or kiss. It hurts when I look at them. I am not happy, for him yes I am, but I want to show him that I am telling him that I have a boyfriend but I don't. I kinda want to show him how I can be happy without him. I want to make him jealous. How do I do that?

your best friend will know that you are faking,just leave it and find someone