Partners of the Month - S2-E18
Revealing mistake: When Schanke, in a huff, packs up his treasures and moves out of Nick's loft, he kicks the box of his belongings into the freight elevator, then gets in and closes the door. If you watch closely, you can see the cord of his duck lamp caught under the door, where it stays even after the elevator supposedly begins its descent. (00:31:55 - 00:34:55)
Answer: Nick was sick and tired of being an immortal bloodsucker. He wanted to be human, fall in love, get married, have children, grow old and die. As for Janette, according to her, she fell in love and the passion she felt "cured" her of her blood lust.