Welcome, space, to MarriageBuildes...
You aren't alone...there have been quite a few spouses on this website with a passion hobby...
Have you read all the articles on this website (links to the right of your screen), about the four rules of marriage? An important one is Policy of Joint Agreement...POJA.
Did you both enthusiastically agree for you to start up a new band?
Can you also see where she is passionate about your marriage, wanting it to be her number one priority...and you aren't being supportive at all?
You guys can meet in the middle...do you want to disappoint the guys in the band or your lose your marriage? It really will come down to that...because choosing to continue with the new band really means your top priority is your band, not your marriage. Won't happen over night...will happen. We live our priorities...and I'm not coming from a wifey point of view here...not siding by gender. I'm recognizing you did this...and weren't in one while you courted, fell in love and the first two years of marriage.
You vowed for a lifetime to your wife...doesn't mean what she says goes...you're each half of the marriage. You can search for "band" threads, musicians...heck, "cars" "running" "hunting" lots of sports which are partners' passions...
How close they were to losing or lost their marriages...how much regret they have because of it...and how hard they worked to get it back, when too late, they realized what their real priorities were.
We choose our lives in every moment...right now, you're seeing her as your enemy...and she remains your partner. She's fighting for her marriage...knowing the odds are stacked against you both...how much care and attention is necessary to get to thriving. Read about the other rules, also...of radical honesty (which I believe you are being with your wife), the rule of time and protection...
Understand all her concerns...her thoughts, feelings, beliefs, perceptions...which is knowing her...intimacy through sharing and being shared with. It's not one or the other...it's where you put it on your priority order...and where you want your whole life to go, not just your music.
Fear gets us into our inner child...where we think it's all or nothing...we have an automatic perspective of all or nothing...not real in our adult experience. You're not crazy and you're not wrong.
You may want to post over in Emotional Needs forum, though. This is about ENs...yours and hers. And it gets a bit more traffic than Resolving Conflict. These forums aren't hard and fast for subject...Infidelity: General Questions II gets the most traffic.
Is this your first marriage? Her first marriage? Any children?
Thank you for being here...for being brave and posting...I think your marriage is a high priority to you.
LA