If you don't want your dog to mark all over your house, you need to get him neutered. My yorkie was neutered and he doesn't mark in the house at all. My mom hasn't neutered her maltese/shih-tzu yet, and he does mark everywhere, but he will be getting neutered very soon. I don't know if it will be too late to stop the marking, but she wants him neutered anyway. My aunt's yorkie was never neutered and he marks all the time!! Neutering is real surgery, but if your vet does the laser surgery, it helps with the healing time and everything
Just ask your vet to use gas anesthesia instead of injectable anesthesia. Gas anesthesia is safer and the dogs come out of it much quicker.
Our dogs are trained to go on the pads and outside. They mostly go on the pads, but they know that they can go potty outside on the grass also.