This is it. I think the design weight for a lot of wheels is about 200 lb. A little over that and you're okay for a while but it will catch up to you.

Just get a new wheel and be done with it. I bought a new, modestly priced (< $120 for both wheels), wheel set for my commuter after I started popping spokes on the original wheel. Solid as a rock. My sense is that unless you get a high-end bike with handbuilt wheels, factory wheels will work good for a 200+ lb. rider for a time, then the spokes start to break. When you break the first one, it over stresses those around it, contributing to the next break in a kind of domino effect. You can either replace all the spokes or get a whole new wheel.

I took care of the commuter hybrid a while ago. Recently spokes started breaking on my single speed and I will soon be building a new wheel for that.

As for the contribution of commuting? The weight you carry might be a small factor, but I think the bigger factor is that if you commute the same route repeatedly, you probably know where the hills are and after a while you attack them more systematically. Whenever I've popped spokes it's been during a climb. Also, hammering away when the light turns green to position yourself in traffic can put a fair amount of stress on the spokes. It's not really that you weigh 230 that's the problem, it's that a 230 lb. rider will put more power through the drivetrain than a 150 lb. rider for the same acceleration.