Need relationship advice

So I’ve been in a relationship with this guy for 2 years now and I’m kinda torn about whether I should stay in this relationship or leave because since getting into this relationship I’ve gained some really bad habits like smoking, sleeping a lot and just not taking care of myself altogether. I’ve gained 50 pounds in just 2 years and it’s kind of stressful because every time I tell him i want to stop these bad habits and I think he should stop as well he will agree at the moment but the next day continue with the smoking and trying to sleep all day, I don’t know what to do anymore because I do love him but I also want to change my life and I don’t feel like I can do it with him.