Hi Speedy, I'm SWC, a Co-Dependant and an Al-Anoner. I echo what Margo and Anna have posted, but from the other side of the fence.
You now know of a trigger, you need to remove yourself from the trigger next time it "goes off", or is about to.
As my A told me, a very long time ago...if we broach near an argument, always know that I (me) will always be right. In other words, he will walk away so as not to get angry, not to feel the trigger. He also wanted me to understand that he is not walking away from me, or the issue at hand, but he's walking away from the trigger until he is confident in himself that we can have a calm discussion to resolve the issue. He knows we can't bury everything that might become a disagreement, but I know that there will be times (not all the time, I'm sure) that "now" is not the time. This gives us both a chance to really decide if the issue at hand is even worth the slightest bit of angst. I have found in myself that the answer is "no". I know I can't cause him to drink or use again but at the same time, pushing an issue about something that may be unimportant (in the long run) is ill-advised for both of our recoveries.
Perhaps you can a similar resolve, albeit temporary, to your wife? Send her our way, over to the Al-Anon boards and she won't feel so alone (if she does) and maybe get some ideas of her own.
Welcome, and keep on, keepin' on.