It sounds like you want/need to vent, but your wife is not a good venting partner. I would just accept that she is not a person you should vent to. You are not going to get satisfaction from it and it's just going to cause more problems in the long run.

I agree with Rose that we don't always need to express our feelings. Talking about certain feelings actually makes them worse -- if you are angry or frustrated and start talking about your anger or frustration, rather than feeling relieved, most people just feel angrier and more frustrated.

We all come home some days and want to complain about the driver who cut us off or the jerky coworker. It's normal. Your wife seems to take it a bit personally, so perhaps it is easier to just remember that and not make those sorts of comments to her. Instead of looking for her to support, look to her as being someone you can find relief with, someone who is completely separate from your problems and frustrations with work.