What to Wear to a Manhiem Steam Roller Concert

Ear plugs. And sun glasses. You're less recognizable that way. (just kidding)
Jeans and a sparkly top sounds perfect.

I'd do the jeans and boots option. We went to TSO (TransSiberian Orchestra) last year and you saw people wearing everything from jeans and T-shirts to cocktail dresses. I would assume Mannheim Steamroller concerts would be the same thing.

I would take the tickets if I lived closer. Love them. Jeans boots and nice top. Let your hair down and go have fun.

It really depends on where you're seeing the concert at. If its at an arena, you will see people in jeans and sneakers to cocktail dresses and you should wear what you want and no one will judge. Anything goes. If its at a concert venue such as a concert hall/theater, typically you'll see more business casual to cocktail attire versus jeans.
In your case, I would consider a few things when deciding: How often do you and your hubby get a date night and how often do you get to dress up? You husband might just LOVE seeing you in a little black dress and heels! Could be a spicy night! If you have lots of opportunities to get glam, then go with skinny jeans, boots, sparkly top, etc, but my vote is most definitely for the dress. There have been times when we've gotten a sitter and when my hubby has seen me come downstairs in a little dress instead of the usual jeans, he's said he's changed what he had in mind for dinner and made a last minute decision to take me somewhere nicer for a bottle of wine than what he originally planned.
Enjoy! It will be fabulous.

I would wear whatever I would feel comfortable in, as the concert will probably be several hours.

I would also wear something versatile as far as temperature is concerned...if it were me, I'd wear slacks, a long sleeve shirt, and a sweater...that way I'm prepared if it's cold or if it's warm.

Depends, where is he taking you for drinks before or after?