Jay was the husband of Sidney Merrick in the Season 6 episode Baggage. He was portrayed by actor David Monahan.
House, who was being accompanied by Alvie, were looking for clues to Sidney's identity in the store where she bought her shoes when they noticed a nearby donut shop. The owner of the shop recognized her and pointed out Jay's business card on a wall because he had won a contest.
When they reached Jay, he identified her as his wife and told the doctors she was a lawyer. However, she didn't recognize him at all. He had called some hospitals when she didn't come home, but although Sidney was a long distance runner, he thought Princeton-Plainsboro was too far away and didn't try there.
He accompanied her back to the hospital, but as he tried to talk to Sidney, she rejected what she perceived was the boredom of her life - work and long distance running.
As Sidney got worse, House wanted to operate on her brain as she thought she had a progressive brain disease. However, as this would have permanently affected her memory, Jay was opposed to it. It was soon out of the question because it was obvious Sidney's brainstem was affected.
However, Sidney was eventually diagnosed with a severe allergic reaction and recovered. Jay was advised to stop treating Sidney with such familiarity because it was obvious she felt the intimacy between them was forced. Sidney soon warmed up to Jay and they started talking again.