Neutering may not help for this problem, but he is the right age to have it done so that marking does not become a problem along with other health and behavioral problems that are associated with an unaltered dog.

If your pup is paper trained, then he thinks it is ok to go potty in the house whether it's on the paper, the floor, or furniture. Another reason he could be peeing on the couch is because of a UTI which you will have to get a fresh sample as he's going potty and have it tested by a vet.

If he doesn't have a bladder infection, then you need to start working on housebreaking him so that he learns that outside is where he needs to go potty, not in the house. Paper training is ok for little puppies who can't hold themselves, but a pup his age should be housebroken.