If I smoke weed my boyfriend will leave me?!?

We've been together for 3yrs,..we broke up for 3months & I started smokin weed..we got back together & now he's saying if I start back he will leave me bkuz he hates it &+ his gma died of lung cancer ...he rather me drink than smoke,idk what to do..I dnt wanna loose him,but weed calms my nerves.. I THINK I MIGHT STOP :))