As an update, tomorrow I will leave for the family program at her rehab facility. It's 3 total days and I assume I will get the answer to Spence7471's questions then.
Part of my homework assignment for the family program was to watch a 90 minute documentary which focused on both addiction, but also co-dependence. I had always understood the term to mean people who were dependent on one another or "loved each other too much" but I came away with a much different perspective. I now know even more that SHE has to make choices to heal and to recover, and that I can support her, but I can't do anything for her. She has to make choices and while I hope they're good ones, in the end, they'll be her choices and not due to anything I could have/should have done.
I've also found support in an unexpected place; my boss went through the same thing with their spouse. Having that kind of understanding in my "other" life at work has been invaluable. It's also heartening to know that their marriage survived and that treatment/recovery is possible.