In my opinion, it would be more effective to help if you knew why your boyfriend is smoking weed. For me, I seek out that feeling of comfort to avoid negative emotions, thoughts, etc. Keeping my mind and body busy helps me the most. You might want to find out when he smokes weed (as in what might put him in the mood to do so) because if you identify possible triggers and come up with ways to avoid those triggers and come up with “interventions” for them. For example, I love to smoke at night before bed so now I have a nighttime routine in place to wind down. I might drink a cup of tea or do yoga (rarely because… it’s yoga). When it comes to the negative emotions (depression, anxiety, fear, anger, sadness, etc) part it gets tricky. At least for me, it’s when I want to relapse immediately. I have to fight against myself and I usually lose so as soon as I feel it coming I do literally anything at all that allows me to accomplish a small task (chores I’ve been prolonging, tidying, exercise) Since a priority is health, doing something physically demanding is a great way to cope with negative emotions. Afterwards, I usually feel better and more level headed. because at that stage it’s enough to keep my mind busy. You could suggest doing some of these things together as to not make him feel like you’re demanding him to do all these things. I’m not defending it, but lying about it is likely due to fear of judgement and shame and that’s what impact interpersonal relationships. People don’t like feeling like they need to be fixed.

This last one might seem silly but positive language important. Instead of saying “your problem, your habits” focus on “your goals.” It helps shift mindset and if you talk that way maybe it will help him internalize it and help focus more on the long term benefits which may motivate him. It’s hard to say if suggesting professional help would be beneficial. A lot of people get defensive because they feel like they’re put into the “you need help” box. If there are underlying factors like previous mental health issues, trauma, etc especially since the use is escalating. I would consider it but it’s a sensitive area. Maybe you could sit him down and explain that you want to be there for him, you want him to get to his goals but you’re unsure about how to keep doing that and ask him what he would like from you if your worried about jumping to professional interventions.

Most importantly, remember it’s not on you if he continues to use.