Hi, while I find it admirable that you recognize how much work your Realtor has done, you need to consider that a contract is a binding legal document between you and the buyers. If you breach it your buyers may also have legal recourse. I agree with Joyce and Masha, you should consult an attorney. Best wishes.
This is a legal binding contract and the buyers may sue for specific performance and you will probably owe your real estate agent his commission. I believe if you want out of this it is going to cost you plenty! You MUST consult a attorney.