Your bisexuality isn’t part of your being. It’s essential to your being. But it’s not necessarily essential to your job or to your relationship with your coworkers… unless, of course, you are challenged in the course of your job to stand up on behalf of queer and/or trans rights or community.
I understand how uncomfortable you must feel having, in a professional setting, kind of slipped back into the closet. I would feel the same way. But the longer you postpone the reveal, the more awkward it will become.
You’ve written beautifully about it here. Perhaps you could start by printing this and sharing it with coworkers you like and deem trustworthy. It says everything you need to say sincerely and succinctly. Wishing you the personal peace you so deserve.