I've been told I was too conservative and that he prefers women who were fun, outgoing, assertive, spontaneous - which translated to I did not give it up or give him the impression that I was going to give it up soon.
I know I may be approaching your question with a negative answer but be wary of men who tell u to be more open, yada, yada, yada and figure out where they r really coming from. If he is someone who truly knows u and cares for u then I would give more credence to his opinion. But if he is someone u r just getting to know make sure he is not stating things about u for his own benefit.
Just my thoughts......