Szeik:

I'm thinkingthat it may be two probelms:

1. Insufficient insulation between your roof rafters that is causing the paint in those areas to dry too slowly because of the condensation forming on the paint in those areas, and

And inexpensive PVA paint that was never intended for use in bathrooms being used instead of a paint specifically made for bathrooms.

If you can afford to rent a thermal imaging camera, I would check out the heat loss through the areas where the paint is still wet. It could be the insulation in your roof isn't up to snuff.

Also, I would check to see the kinf of paint used by the contractor. Paint is one of the most poorly understood technologies in the entire paint center, and I wouldn't expect a contractor to understand paint any better than your wife.