My 8th month old dog still isn't full housebroken. He knows its wrong to go inside the house but he still does regardless. About 90% of the time he goes outside, but once or twice a week he just decides to poop in the house. Usually he does so secretly. He knows its wrong but he's not going outside. I dont know what I'm doing wrong. Everytime he goes potty outside I give him a reward. What should I do?