Oh Boy!
I hate to say it, but I think I've been the bitch in this conversation a few times. And when I was, I was generally mad or frustrated about something. Sometimes I could put my finger on it but just didn't want to say anything and other times I really didn't know what was causing it I was just generally aggravated.
From your previous posts, and if I am recalling correctly, you help out a lot around the house. My ex didn't. That was a source of a lot of my frustration. Which led to encounters like the one above. And problems elsewhere in our relationship - like the sexual issues you've talked about.
I wish I could offer some sage advice; something that would make you feel better about your situation and would help you be able to fix it. But I never felt comfortable opening up to my ex (I know, so many warning bells should have gone off there!) and so I couldn't, wouldn't, or didn't tell him more when things were bothering me. When I did try to talk to him I felt like he wasn't hearing what I was really trying to say and that made matters worse.
I would say first off, assure your wife you do not think she is a bitch (whether or not that is the case). Explain to her how YOU feel, as much as possible without blaming her for your feelings. Give specific examples of behaviors (again trying not to blame her) that lead you to believe one thing or another.
Given the recent news about lawsuits and whatnot, you may or may not want to do this, but I also say, SNOOP! My thoughts tend to go round and round and I never get anywhere with them myself, but even so I was trying to journal or talk to friends to try to resolve some of my/our issues on my own. Your wife may be doing the same. You very likely won't like what you find, but if you're really intent on working on the issues - or on the fence about whether or not they need to be or can be worked on - then anything you find will help you come to your own decision.
Just don't tell your wife how you came about your knowledge. Some things are better that way. She doesn't need to know you looked through her personal life; the one she tried to keep hidden from you. It will make her feel violated and untrusted and disrespected.
Maybe it's not such a good idea after all! LOL I just know that I sometimes wished my ex would come across my ramblings and see that it wasn't just him I talked in circles with and there were some actual small things he could do to change. They weren't things that were big enough I felt like fighting about them (pick up your socks!), but adding up day after day after day they pushed me to my wits end.