Yakamishi,
What you're going through is perfectly normal. It sounds as though your WW may not be on the same page as you with respect to appropriate behaviors that are helpful for R.
However, I also believe that you should be very explicit with her instead of implying that she should pick you. That is, if you don't feel comfortable with her going out drinking, I would recommend explicitly stating that, and tell her that you feel uncomfortable with her doing that at this point in R (which I'm guessing is still relatively new, especially if her 'going out' was a part of her A). If she doesn't respect your concerns, then that says a lot about her commitment to R.
My WW and I like to go out whenever we can. However, the difference now is that we try to go out together, whenever possible. If not, I may go with a couple friends to a familiar bar or something, or she'll go with a familiar friend to a bar for drinks. However, our primary goal when going out is to try to go out together, which is usually the case 90% of the time we're going out.
Going out can be a great time, and help ease tensions, feelings, etc., so I don't ever recommend against it. However, I think it can be done in a way that is supportive and 'safe' for both people.
In short, next time you feel uncomfortable with your WW going out with coworkers, I would express this. However, I would express it WAY prior to the fact (like, say, tomorrow?) so that it doesn't seem as though you are reacting to her decision to go out, and instead, and bringing up a real concern of yours. That way, she has time to think about it and process what you're expressing, and not while she is, say, putting on her make-up to go out in an hour or two, if that makes sense?
Best of luck!