Go for it, or tell him "we tried FWB, I really enjoyed it but would rather be friends like before".

You were both exploring. You can't figure out what the other person found without talking about it. Close friends talk things over. Time to get to it.

You didn't fuck up. She did. Multiple times a day, for over a year.

If she won't respect your needs during the peak of your career, does she really love you in a way that is deep and meaningful to you?

Having experienced something similar, but not exactly the same, the answer is "no".

Lay it out for her. Respect who you are in public or get out. She can still have a private name for you if you're feeling generous enough to grant it. Words are meaningful, names are even more so.

About your stage name:

"Pen names are masks that allow us to unmask ourselves."

— Terri Guillemets.

About the intimacy of her being allowed to keep using your real name in private:

"When you love someone, you say their name different. Like it's safe inside your mouth."

— Jodi Picoult.

​

Names are powerful, meaningful, and important. That's why this would be a dealbreaker for me. She doesn't share the same values as you do.