Probably the way I'd handle it (and it may not be the right way) would be to let it go for now (she may just have been moody and just wanting to complain at the time), continue to be the "new person" you've changed into with regard to this. And the next time something like this occurs point out that you've changed and this no longer bothers you.

Or, if you want address is, but in an easy-going, matter-of-fact manner. Saying something like... 'You know how the other day this happened.... it's funny but that kind of stuff no longer bothers me. I'm not as concerned about spending money like that when I know we're having a nice time."

I know it's frustrating. Sometimes we do truly change and spouses see us as reacting in a way we would have done 10 years prior.

It's interesting about your previous post how snooping is such a negative thing. I think so too and yet I find myself wanting to do that lately to figure out what's going on with my H. I even broke down and ordered some spyware for the computer. I kind of regret this now because I think I need to just let this stuff go and move forward in my life. :-(

There is no arriving, ever. It is all a continual becoming.