It sounds like you have a real dilemma.
It may be best to confront your ex-boyfriend and explain to him how you are feeling (leaving out the part about cheating as this will only hurt your chances with him). It is possible he feels the same as you do and is waiting for a sign from you to re-start a relationship.
My only suggestion would be for you to think about why it was that you previously cheated on him. If the reason still stands, it may be futile to try and re-start something with him as it will only lead to a painful break-up. But if the cheating was a one-time thing and you realize it was a mistake, I would suggest talking to him and seeing where he stands on the matter of getting back together.