My bathroom has no real ventilation save for the bathroom window which is usually closed when taking a shower. It was suggested to me that when I repaint I should use exterior paint as it was made to withstand the elements such as moisture. Has anyone had any experience with doing this? Is there a difference in the paint durability? I usually have a problem with cracking in the paint.

Stick with interior paint and strongly consider adding in a vent fan.

Exterior paint is formulated to withstand the elements. What most don't realize is that the main "element" that harms the paint is sunlight. An exterior paint will not perform any better in your bathroom than a good quality interior paint. Both will crack if there is excessive moisture in the wall surface under the paint.

It does sound like the cure for your problem will be to install a vent fan and to use it. Get one with a low sound to it - you'll hardly know that it's on.