Potty Problem with Pudge

We have three dogs. I love each of them equally, but at the moment I'm at my wit's end with one of them: Pudge the Boxer.

We purchased a carpet remnant to replace the old tattered one that was in the dogs' area in our house. It's a nice space on the wood floor, near both the kitchen and the living area. I laid down carpet pad to protect the wood flooring from the scratchy underside of the new, plush carpeting--and to provide the dogs with a little extra cushion for lounging and snoozing. 

Pudge has suddenly taken to peeing on the carpet. He's going to be two years old this week, and we've never had a problem with him peeing in the house--at least not since he was a little puppy. I have not been able to bust him in the act, but my husband's middle daughter heard the distinct sound of peeing, and when she ventured over to see what was going on; the only dog standing was Pudge. Guilty? I think so.

Pudge's penchant for peeing on this new carpet has me a bit nutted up, as I don't want to have the new purchase destroyed--at least not so soon!

It's incredibly difficult to catch him in the act, as he's sneaky. But there are consistently wet spots on the carpet where the deed has gone down. We have been taking him outside for potty breaks more frequently, but it still keeps happening!  I don't know if there's something about the new carpet that he feels the need to "mark it," or what. 

What do you think? What can we do?!

~Jacklyn