Thanks everyone for the great advice. I feel like I need to clarify.....
Our vet IS a WONDERFUL vet that we've been going to for 15 years. I would trust her with my CHILDREN if she were a pediatrician. We have done all the necessary testing and he does not have a bladder infection. I will, however, ask her about stones. And He IS NEUTERED. Both of the boys are. They are brothers from the same litter and when they were reunited, they have been best of friends. Bentley (the one peeing) is more the cuddler than Jasper so if anyone should be having jealousy issues, it's Jasper. But neither of them really do.
Also, this isn't a 'sudden' behavior... it's something we had mastered after getting him last December, and didn't have to worry about until the weather got cold again.
We do have a doggie door, and the dogs have in and out privileges at will.
We did the homemade belly band last night, and he hated it. I'm going to use it at night, and when I'm not home. I hope he learns to not hate it as much.... he pretty much stayed on ONE spot the whole night. lol