I've never really formed a true opinion on the subject of marijuana smoking. I have nothing against it. I've tried it myself on a few occasions, but in all honesty, alcohol is my drug of choice to kick back and let go.
I'm only bringing this up because the herb is, I guess, always mixed with tobacco before rolling. So if you quit smoking cigarettes but continue to smoke marijuana, you're still smoking tobacco.
I know people who have quit smoking without giving up weed, and they remain quit. So I know it's possible, and it's for this reason I don't have an opinion.
However, I would imagine that by continuing the smoke marijuana, you'll never really get the health benefits of quitting smoking. I don't think you'll ever really rediscover what it feels like to feel good again. You're still inhaling toxic smoke, so that can't be a good thing for your health and vitality.
In any case, I'm not going to tell you that you shouldn't be smoking pot, but I would ask that you consider quitting that too, just for health reasons. It will make your quit that much more satisfying.