In a funny way, it's the ultimate test of your own commitment on so many levels.
The reasons a partner will continue drinking are myriad. Sometimes they are completely benign in that they just don't get alcoholism. At the other end of the scale is the "your behavior has ruined my life and I'm going to do what I want to do now so feck you." In between are issues of control, thoughtlessness, selfishness, dependency....endless really.
The main thing is it's your sobriety. Their reaction and everything around that is essentially a product of your/their drinking or both and needs to be dealt with in time, for better or worse. And it can and will be done if you stay sober.