Dog Marking His Territory?

Help! We just brought a new puppy into our home and our 2 year old papillon starting peeing everywhere. Is he marking his territory? Is it some sort of rebellion/jealousy? Or maybe confusion, since we are potty training the new puppy and have puppy pads out. Any solutions or tips you could give would be much appreciated. Our papillon is neutered, and hasn’t marked anything since then. We’ve had him since he was 12 weeks old, and he’s been our only dog until now.