Dr. Zeltzer and his wife are noted sexual adventurers to the point they may engage in BDSM and rape fantasy. For example, he knew he loved her on their fourth date, but couldn't say it out loud because he had a ball gag on. He misses her while he is at work, so he has a webcam so he can watch her at home, usually having sex with other couples. ("My Nah Nah Nah") He and his wife also once drugged Jordan and Dr. Cox into unconsciousness, although it is unknown how they may have taken advantage of this.
Dr. Zeltzer is also sleeping with the wife of Dr. Lebanthol ("My New Old Friend"), a rival oncologist at Sacred Heart, and has been known to visit prostitutes.
- When Janitor asks Zeltzer about him and his wife, and Zeltzer replies with the story about the ball gag, Janitor coins the phrase "I've just been Zeltzered".
- Dr. Zeltzer appeared in J.D.'s last fantasy at Sacred Heart, telling him that they could party with hookers after J.D.'s last shift. ("My Finale")