S2·E18 On the Rebound

Episode airs in syndication; Ginger continues a hot and heavy courtship with Arthur Schillabe, Charlie pursues Gina with some force, and Jeff tries unsuccesfully to manage a rendezvous with Caroline Hailey. Unlike his tender romance with Ginger, Jeff (out of character) and Caroline go to her rooming house, and strip down to undergarments--Caroline throws his shirt on the hotplate, starting a fire. Gina and Charlie burst in to help, finding Jeff in his underwear and Caroline in a slip. They successfully meet at a hotel, after which Jeff complains to Judy about the lack of real feeling. To which (figuring out that Jeff slept with Ginger at some point) Judy knowingly informs him the earth only moves when you're in love. This points Jeff back toward Ginger, and gets the ball rolling.