You need to go back to basic training. Which means the dog is either in a crate, outside, or leashed to you. That way you can get him outside to potty when it seems he needs to do.
If possible, block off the living room so he cannot go in there.
more training links on left and right
Our Lacey, will not even poop in the yard. She prefers to go to the wooded area in our backyard or a ditch in the front. When we were visiting relatives on a farm for a week she would walk out into the cornfield to poop. In fact she was visibly disturbed when the other dogs would poop in the yard. She would look at them as if she was thinking, "But why are you pooping in the playground?". Even if we picked it up she would avoid running over the spots while playing.