I agree with the observations that you decided to go into the store because you had not accepted your sober status completely. You left a crack of a door open somewhere.
Originally Posted by
VigilanceNow 
So I'm wondering... what is everyone's response to this question: why and how does sober you go to the liquor store when I think we all know (since we are on this site) that drinking is a terrible idea? Any suggestions on how I can explain this to him without sounding like I'm trying to justify this action/make excuses for myself?
Sober me does not go into a bottle shop alone. I've been into a bottle shop accompanying friends / family when they were choosing wine, and I hung around the entrance. Nothing in the store had any interest for me. If I'm in the supermarket, I have as much reason to go down the booze aisle as I do the cat food aisle. I don't own a cat.
Originally Posted by
VigilanceNow I still haven't nailed down what exactly my triggers are, because to be honest when I was actively drinking all the time, there didn't seem to be any rhyme or reason as to when I would do it.
I think your boyfriend has a suspicion that you did not do "enough" work to prevent a relapse. I think he's right. I'm not trying to make you feel bad, because we all know this is not easy, but the logic is inarguable - if you relapsed, then there IS something more you could do this time around. I'd start with this statement here, where you say there was no rhyme or reason to your drinking. Were there really no specific times of day, places you went, feelings you felt, where you drank more often than other times? What were you thinking on the day you went into that liquor store? Or the days leading up to it? I don't think the AV is some disembodied demon that jumps into us from nowhere on a clear day and instantly transforms us from sober thinking to wanting a drink, it preys on certain pre-existing loopholes and weaknesses in our mind.