My wife can be this way (she says she is not this way). I just have to work at it. I take a deep breath, remind myself that relationships are hard work (but worth it) and get myself ready for some emotional gyrations.

For me "reflection" usually works.

It goes like this:

{my observation} leads me to believe {my guess as to what's in your head}

So:

Honey, you seem down lately I'm wondering/thinking/concerned that you think I've been doing/not doing whatever.

No? Well you do seem down, could it be you're thinking this other thing?

Gee, you seem angry at me, could it be your thinking I'm on the internet too much?

I find if I show real concern for our relationship and just keep "reflecting" ("now you seem worried, is there something wrong") after a dozen guesses she'll usually pop and start spewing all the things that are in her head.

Usually it's damn painful to listen too - lots of "you do this, you do that, you're always causing me trouble" talk. I just hold on for the ride. Keep cool. Don't panic. Then reflect it all back: "so when I did such-n-such you were thinking I did it because blah."

Work on focusing each issue so you see it from her viewpoint and you can reflect it back to her in a way she agrees with.

It goes on and on. Then I pick out the valid things (somewhere in there there is usually a few valid things) and I set my mind to fix them. I tell her I'm sorry. Then I work on getting her to see the valid things from my standpoint.

When I did this I was thinking this other thing, I wasn't meaning to cause you this problem.

On it goes.

This has got me through 10 years but time is still young. Ask me in another 40 if it really works.

Good luck.