March, unfortunately we As who have developed alcohol dependency are rarely able to moderate, or can only do it with super-human effort. I'm not just parroting some AA doctrine here (never went to AA) but relating my own and others' experience. Once the connections are made in the brain you never lose them, and moderate drinking just acts as a maintenance dose that eventually escalates into excess drinking.
Your EXW will gradually or even quickly increase her intake. She may well be doing it right now but hiding it from you.
This is not to say don't get back with her, but do go in with your eyes open or you'll be surprised and devastated by what happens next.
From what I've just posted, you can see that 'supporting' her however kindly meant, becomes irrelevant against the chemistry going on in her brain.