The reason for this is that shy men are more concerned with avoiding the social catastrophe of asking you out and failing than they are of getting you.This is what prevents them from taking the initiative in the first place.You will probably get frustrated at his lack of response to your initiatives.The biggest problem is that it won't be clear to you whether or not his unresponsiveness is a product of his shyness or his lack of interest in you - because it could be either one. His persistent willingness to hang out with you might be stem from a real interest, but it also might be a manifestation of his unfulfilled desire for female attention; he could just enjoy dabbling in the idea of a relationship but at the same time not like you enough to want anything serious with you.
Aside from their innate male tendency to overlook anything that isn't spelled out in black and white, shy men will by default doubt any sign of your affection.His masculine instincts will kick in, and in some cases you can end up with a man that acts towards you the same way that a confident man would have acted from the outset.So, if you do choose to initiate, do so only during the early stages of dating, that is, until he builds his confidence and comfort around you.That offense will reflect negatively on you and the relationship.So be careful about how much (and which) initiative you take.