If we're used to doing the same dance, and our dance partner changes from say, doing a tango, to dancing the foxtrot, then it can take some effort and maybe even some practise to get the new dance steps right, and get in sync again.
The enjoyable part of drinking was clearly something you did together, and at that simple level, it's understandable that your partner - and maybe you as well - miss that. However, things have changed and it seems you're seeing that going back to light social drinking isn't something you can do right now.
The other thing that can happen when one person makes changes is that it can become clear that perhaps you weren't the only one with a problem. That's not to say that your partner has the same problem, or needs to make the same changes as you, but if someone else is consistently drinking more, and more often than you then it can be easy to disregard your own habits as not a problem.
It's like the old joke - you've only got a drinking problem if you drink more than your GP (apologies to my general practice colleagues…)
So it seems a conversation is needed. Perhaps you can talk to her about the support you need, which might include not asking or encouraging you to just have one or to drink with them.
You may also want to acknowledge that the change is hard for her too, and while she may or may not want to do something about her drinking, part of you changing how you use alcohol is acknowledging that it is making a change for your relationship - specifically the role alcohol plays in your lives.
It may be helpful to talk about how you can do things differently together, including different shared activities, or developing new ways of relaxing and unwinding together. If she does want to continue drinking then deciding together how to do that in a way that is safe for you is important - that may mean going out to socialise with friends, or it may mean having no alcohol in the house for a period of time.
And if she's really struggling with the change then there is always Al-Anon, which is the support network that exists alongside Alcoholics Anonymous (AA) for partners of those with alcohol issues. It can be a useful place to get support and untangle some of these patterns.