If you're newly sober or trying to reduce the frequency in which you drink or use, being around someone who still does can be hard.
Whether it's a room mate, a partner, or a best friend, distancing yourself is difficult, because not only might their behaviour trigger you, too, but you also see all the patterns and unwanted results of your friend's behaviour.
As with any tricky situation, having a game plan is essential in this scenario, and here is the one I propose:
First, define your personal recovery goal.
What are you going for: full sobriety, drinking only on the weekend, no weed during the day? Be specific about your preferred future and try to stick with a recovery goal that is realistic (e.g. cut out a cigarette until you feel like cutting out another one vs. smoking a cigarette less every day).
Then, define your friend's role in this.
How can your partner or friend support you in this? Again, be specific: Would it be helpful if they hid their drinks, smoked only in their room, or would agree to go out with you without drinking? Once you know what would be helpful, it's very important you actually let them know, as well.
Lastly, put yourself first.
People are creatures of habit, and unless we really, really want to make a change, it can be extremely difficult to stick with a plan, in spit of all the best intentions. If your friend or partner is dropping the ball on what they said they would do to support you, refocus on yourself and keep your priorities straight; at the end of the day, each of us is responsible for our own life, and recovery is not for those who need it, but for those who want it.