Can he make me sell my house if the mortgage and deed was in my name?

The name on the mortgage is not relevant here. Its who is on the deed. Adding the fiance to the deed was a huge mistake because you just gave him 1/2 of the equity in the house. Either you pay him money to get him to convey 1/2 the house back to you or he can bring what is called a partition action. In a partition action, either of the deed owners to the property can force a sale of the home. After the mortgage is paid, the equity is then divided between the parties. You can bid at the sale and can buy back the home but you will still have to pay him 1/2 the equity. How is it that you were able to add him to the deed without the consent of the lender and have him not be on the mortgage too? I would figure out how much equity is in the home and give him half of that. You will not get significant money at a partition sale and selling a home can be tricky depending on where it is located. Never ever buy anything with anybody to whom you are not married.