I'd say you are fucked. Despite what the first poster said, although it sounds good in theory, I'm a chronic meth user of about two years, and unlike you, I don't have a steady connection or the finances, so I end up getting a gram every few weeks and binging for 4-5 days then being in absolute hell for a week, then a few weeks of rapid cycling depression/mania.
If you do quit, be ready to go through absolute mental agony, first you will do nothing but eat and sleep for weeks, then, you will have many months of no motivation or energy, seriously, even cleaning up your home, combing your hair, and going outside to do errands will be a massive undertaking, not to mention the severe mood swings you will go through, you'll feel extremely depressed for long periods in the day, then suddenly, you'll get this ridiculous rush of manic euphoria that lasts far less than the depression. Oh, and any cognitive tasks will be much harder for you, not to mention you'll be very anti-social, anxious, and fucked.
How is he supposed to exercise when he's going to have zero energy or motivation? I do daily very long walks and dancing on the weekends, plus weight lifting when I can, but forget dancing without meth, and the walking or lifting cannot be done right after a crash. I also do meditation, I highly recommend that, but seriously, I've tried everything and it is just torture. I suppose you are lucky, because at least you don't crash like hell all the time like I do, but if you do stop, you'll have a much harder time than me if I were to stop.
EDIT: I don't want to sound cynical here, positive thinking is extremely beneficial, but it will be a brutal process to undertake, even with support, positive thinking, eating right, sleeping, exercise, meditation, it still fucking sucks. It actually isn't that hard to quit though, the real problem is staying quit. You'll make it a few weeks and then relapse hard, at least that's what keeps happening to me, maybe you have more willpower than I.
Meth withdrawal is worse than opiate withdrawal, in my opinion, because at least with opiate withdrawal, as hellish as it is, it basically involves being really sick for awhile, then MINOR (in comparison) psychological withdrawals. Not saying opiate withdrawal is fun, it is a seriously fucked thing to go through too, but meth withdrawal is far more evil as it were, because it takes much longer to truly get out of withdrawal than opiates, but it is so much more subtle than opiates, because aside from the initial crash of sleeping and eating, you don't really have any visible symptoms so you think you are fine and beat it when you are in a suddenly good mood in the mood swings, then it reverses and you get really fiending.