How Do I Stop Myself?

I seem to have this switch in my head that activates whenever my SO talks about money. After the switch is thrown, I become this evil, guilt-inducing asshole about money. It complicates matters that we run a business together and money is a bit tight and she's been underpaid. I'm finally able to double her salary this month and then, instead of being normal during dinner, I went on a rant about how I couldn't afford to buy holiday gifts because of the extra money I was giving her. I knew it was wrong from the second it came out of my mouth, but I couldn't stop it.

Afterwards, I feel like a complete and utter asshole. My SO is usually crying  in the bedroom... she's starting to hate me and I can't blame her. I feel terrible, like a worthless scumbag.


How do I stop this from happening? How do I stop hurting the one true person I want to be with for the rest of my life?


FYI, both of us have ADD. We have been living together for two years.