I confess to have had spoke problems in the past. I currently weigh in at 290 lbs. In the past with rather thin section Super Champion rims, the only way to keep spokes from breaking was using 48 spoke wheels. Now with deeper section rims like the Velocity Dyad, I feel just fine with 40 spokes. I also have some older wheels with fairly deep section rims that seem to be hanging in there with 36 spokes, but I prefer 40 just to be sure.
The deep section rim reduces deflection, which reduces the cyclical loading of the spokes, which eventually causes fatigue failure of the spoke.