Everyone gives different advice, but here's my thoughts:

Nobody can quit alone. If you're boyfriend is as encouraging as you say, then you should be able to turn to him when things get tough, when you fall off the wagon, etc. You should tell him what's going on and not be sneaky.

There's no reason to feel awful about falling off the wagon, unless you don't get back on again. You will slip. You will have relapses. You will be tempted beyond belief. But the only shame is giving up.

The biggest advice is what they tell all addicts (of one sort or another). The best way to break a habit is to replace it with a good one. Differentiate between withdrawl stress and normal stress. When you notice withdrawl stress, or get that behaviorial urge, recongnize it and deal with it by doing your new habit. Over time, you'll learn to change your lifestyle from a smoking one to a non-smoking one.

I hope this helps. Stay strong. We're all in this together.