It really depends on your DOCS and what´s your relationship with them and with the lady ( i.e. are u a recreational week end warrior or a full blown addict? are u somewhat functional-able to maintain a life-work-drug balance or are u killing yourself that s why the lady is giving you an ultimatum? are drugs affecting your relationship or she s asking to quit because she is a 'just say no drugs are evil" kind of person? etc) .
If you were already contemplating quitting, maybe she can be a further motivation to stay sober. But if "you are doing it for her"only, who knows, anything is possible it might even work, but is more likely to end up in a shitshow of lies guilt self contempt using behind her back & 50 different shades of drama.
So between women and drugs I ld choose honesty, with myself and the woman involved, I m this I do this I can promise you this but not that etc.