It sounds to me like you have been reading, " The Rules". This book came out a few years ago claiming that playing hard to get was the way to "Catch" a man. The main premise of this theory seems to be that men like the challenge of the chase and will not be interested in a girl who comes on too strongly. This seems to be your fear.
It All Depends on Your Goals
My opinion is this...If what you want is dates and excitement and control, go ahead, be distant. Yes, this sort of thing does keep a certain type of guy interested. He finds it exciting to pursue and attempt to "capture" you.
However, if what you want is a husband and/or a lasting, committed relationship, BE YOURSELF!
A Good Relationship is Not Built on Games
A good relationship is not built upon game playing or mystery. It is built upon knowing each other completely. If you are a forward person, don't you think a man should know that before you get married? If you are pretending to be someone you aren't, he can never get to know that real you and if you do end up getting married, the real you will come out and he will be understandably shocked and concerned at your personality change.
If All He Wants is the Challenge, What Will Happen if You Get Married?
Also, if you do meet and marry a man who is attracted to the challenge of the hard to get, what will happen once he has "Caught" you? If you are no longer a challenge to him, he will likely move onto a new prey, perhaps the young girl in the office.
Do you really want this type of man? You should marry an honest, sincere, sensitive and trustworthy man. This type of man can smell phoniness a mile away and steer clear of game-playing girls like you. If your current beau is expressing his dissatisfaction with your games, he may very well be this type of man.