Fantasies about friend

For a few years now when I am horny, I pretty much always fantasize about women; at first it was women I would create with my imagination...but then i started thinking about my best friend that I’ve had since I was 6-7 years old. We are in our mid-twenties now and she’s honestly one of the most important people in my life. She has identified as bisexual for quite a few years, and I’ve kind of privately identified as that for a few years despite having no experience...but damn do I want to! And not only do I want to be with her sexually, but maybe romantically as well. However, she is happily in a relationship with a man, and I am honestly glad she has someone that makes her happy. I’m not asking for help...I just need to confess that