I generally agree with this answer from @sf02, To get back to the old relationship is going to take a lot of work, but the most effort required will not be on your part.
It is clear that this discovery has awoken/provoked a prejudice within your boss, the only way to fix this is for them to realize and overcome this prejudice.
If everything else was great about the job, then try to work it out but at some point you will have to draw the line between what level of effort and sacrifice on your part is reasonable.
- Just be careful to not overcommit or compromise your own work-life balance. If your intent is to work harder or longer temporarily to get back to the previous situation you would be creating an unsustainable 'new' image of yourself, which you would have to maintain perpetually for fear of a relapse in the relationship when you decide to cut back down to normal.
Overall, in the workplace, you should be judged on your effort, ethics and behaviors inside the workplace, what you do outside, should be your own. IMO a good workplace should champion individuality and diversity of thought and exercise outside of the workplace, it keeps the mind healthy and helps prevent burn out.
In reality we're all human and it can be hard to not blur the lines between working relationships and friendships/personal relationships. As with all relationships, if there are differences that cannot be reconciled, its probably time to move on.
I once worked in a similar scenario (Software Dev/IT support), was always picked first for attending conventions or going on site to the high profile customers. Generally both "perks" would extend outside of normal business hours. Then my boss discovered that my wife was a primary school teacher, I declined one trip to a convention because it overlapped with a school function... In a nut-shell, it turns out he had very low respect for teachers.
I decided to stay, even tried to 'fix' things, like you say by being better at my work, but things still degraded over time, then a new employee filled that 'void' for my boss. After time there was a discovery about his hobby of wood working and the cycle continued.
What I learned is that this prejudice may not be directly related to your band, it could be as simple as your boss assumed you were putting in extra effort outside of work hours, a quality that is easy for management to respect, but now they realize you are directing efforts elsewhere outside of work. Now they have to re-evaluate all previous assumptions, now they are disappointed, perhaps they saw potential that now they think you are squandering. Either way, in business terms, the projected value of your stock just plummeted.
- perhaps it was your fault for being too good in the first place (jokes)
Having done it the wrong way in the past, my recommendation for you, if you do want to fix this:
Identify the problem
- If you can identify the root cause of the issue from your boss's side, either through work colleagues or careful detective work, then this helps you target what becomes
You will have to confront your boss face to face about this, you have to call them out.
- This sort of discussion needs to be done face to face, because your body language and facial expressions come into play, its easy for someone already biased/prejudiced to read text and interpret the tone and meaning behind it in their own way.
- A text based response can be seen as aggressive/passive aggressive
- People generally respect you more if you can have this conversation in person, one of the key elements here is the level of respect has changed.
- Be aware that they may not be aware of their behavior, management types can often be too egotistical (there's probably a better word... they may not be able to see past themselves...)
- Bring zero emotion into the discussion, do not let it flare up, this is business.
- See the point above about facial expressions and body language, you need to find a way to be comfortable with this discussion.
- Yes it is a discussion, not an argument, be concise, you're not on trial, even though it may feel like it.
- Simply state your work ethic from last week and today has not changed, yet the attitude from your boss has changed and importantly: you do not accept it.
Hear them out
- Once you've stirred them up, you have to let them say, what they are thinking but are too polite to say, its the only way to get to the root cause of the issue.
- Give them permission to say their mind, this can be the hardest bit, whatever they say next you have to be able to commit to yourself that its not to be taken personally, its about letting them vent their emotions and you can't judge them for their thoughts because lets face it, we all have bad thoughts, but we don't voice them if it's inappropriate to do so.
You will have to offer something, this is a negotiation
- Although you shouldn't have to, we're dealing with your boss's emotions now, you have to demonstrate that you are willing to work on this
- Do not compromise yourself here though, you can offer assurances that your extra curricular activities do not go to excess and that you always get adequate rest to ensure you are fresh and alert for work but do not offer to cut it back because so far you have managed to maintain a healthy work/life balance.
Finish with an assurance that you wont let this affect your work, but things must change
- This shouldn't sound like an ultimatum or a threat, its a simple statement of fact that you are happy to continue to work, but this new attitude is affecting your ability to do that well.
The problem of course with this course of action, is that it appeals to a reasonable person, and a reasonable person in a management position who would appropriately respond to this should not have formed such an unreasonable attitude in the first place... So we've uncoverred a paradox here that means the likelihood of this working and getting back to the original relationship is very unlikely, that is not to say that you can't mend it into something else that is acceptable, it's just not likely to be the same.
Cheer up! Going through this experience and exercise in some form is character building. You need to learn how to stand up for yourself, if you can learn to make lemonade out of this lemon of a situation it will help make you a good manager in the future!