Bathroom Paint

I have always used Benjamin Moore paint for everything. This time around when I went to the local paint store I was told of a new paint, Bath and Spa and so I gave it a try. This decision was the worst I have ever made. The paint shows drip water marks on the floor after someone takes a shower from the ceiling to the floor. We have a large fan that does indeed take the moisture out of the room. It is put on before we run the water. It has gotten so bad that the paint started to peel in some places. We now want to repaint and have begun on a small wall using a primer. No sooner did the paint dry that it started to peel from beneath. I am now at a total loss as what to do. I should have never used this new paint. We have lived in this house for 20 yrs. and never a problem since we used this paint. Any suggestions or advice as to what to do now aside from probably stripping the walls down completely ?