You can take your house off the market. Brokers can insist on keeping the listing active for the duration of the contract, but you don't have to cooperate in showing your house, and there's nothing they can do. Most brokers will let you terminate the contract but will ask - or may even try to get you to sign an agreement - for you to use them when you change your mind again and decide to sell.
If you should sell your house during the time the listing would have been active, they may raise an issue and sue you for the commission you would have paid. People will cancel listings so they can go around the broker and not pay a commission, when they are approached by someone that knows the house is for sale and says, "Hey, I'll buy your house for this, and if you don't have to pay a commission, you'll still have more than if I went through a broker and paid you full price."
So be absolutely certain that you do not want to sell and will not sell, before you get out of the contract.