I had this problem. FIxed it by doing 3 things. 1) Make sure your saddle is wide enough so your sit bones actually make contact with the widest part of the saddle in the back instead of having the soft inner tissue rub the sides of the nose----unless you are a skinny racer type, try using a "women specific" saddle--which are wider and painted a different color but are otherwise the same as men's saddle; 2) make sure your saddle is leveled or tilted down just a tad; 3) learn to "dip your hips" or "spill your pelvis" when riding so that your weight is distributed between your arms and the back side of your sit bones.

sitting upright and bent over on a narrow saddle that is tilted up is a recipe for numbness in the nether regions.