Can the landlord keep my deposit if we never moved in the house and there was no contract signed stating he would keep it?
Unfortunately, whether or not you moved in, you appear to have had an agreement to move in. And such an agreement constitutes a lese, which is a legally binding contract (even if it isn't in writing). Therefore, you were contractually obligated to pay rent in exchange for having the apartment available to you. Assuming that the landlord honored their side of the lease by making the apartment available to you, it's not the landlord's concern when or not whether you move in; you still have to pay. At this point, the landlord may sue you for the rent and/or may also apply the security deposit against the rent that you owe.