BELLY BAND!!!! The belly band is kind of like a diaper for boys. You can get it at petco or petsmart. It saved my life and my relationship.
LOL My puppy started marking EVERYTHING at around 8 months. Once I put the belly band on him and he tried to mark his spot, no pee actually got on what he was marking, just in his diaper. So defiantly put sanitary pads in it so you don't have to keep washing it, you can just change the pad. He eventually caught on after wearing the band in the house for a couple weeks.
Good Luck and hang in their!