The Blame Game

My wife and I are stuck in a vicious cycle of "the blame game."  I'll ask her a question, like "Do you know where the attachment for the vacuum is?"  She'll hear it as a criticism, as if I said "I can't find the attachment to the vacuum and it's your fault."  She will respond by yelling "I DON'T KNOW."  I'll respond by saying "Why are you yelling at me?"  And she'll say something like "I'm tired of being blamed for everything."  And I'll say "I wasn't blaming you for anything.  I was just asking you for help finding something. And what I get is yelled at."  And then I'll say something like "I can't even ask you a simple question anymore.  I feel like I'm in a mine field."  And then it escalates.  And as I write this, I realize that my making that last statement is what escalates it into a fight.

I know I can't get her to stop thinking I always criticize her, because sometimes I DO criticize her.  And I've been working on doing that less, and complimenting her more.  I bite my tongue a lot, but sometimes I just have to say something.  But so often she THINKS I am being critical when I am not.  (Maybe that is a sign of how critical I have been - sigh.)

So my question is - how do I deal with her anger, insults, sarcasm, etc. when she feels I have been critical but when I haven't?  And to those of you who say "just ignore it" - I'm sorry.  I've tried that, but I can't just let it go.  I am beginning to feel like a battered woman.  Someone who is verbally abused.  And I know SHE feels like she is constantly criticized.  I know that because she ends up saying very hurtful things to me as a way of striking back when she DOES feel criticized.

So here's the situation:  she feels like I always criticize her.  I feel like she's always snapping/yelling at me.  Hence, we are stuck in this "blame game."