Aurora, I'm like you. I COULD have just one drink with dinner. But then the thought of MORE would start fermenting in my brain. And I'd be looking for the next "opportunity" to "prove" I could have just one. Or, heck, just two. Oh, and maybe one more before bedtime. Just as a nightcap.
Then, as the others have said, I'm right back to obsessing about it and it is only a matter of time until I want to get drunk.