Inconsistency: George and "I love you"

In "The Ex-Girlfriend", George tells Jerry that he told Marlene that he loved her. Yet in a much later episode, there's a conversation between George, Elaine, and Jerry: George: "I think I'm gonna tell her that I love her." Jerry: "That's a pretty big step Georgie-boy. Are you confident in the I love you return?" George: "50, 50" Jerry: "Cause if you don't get that return...that's a pretty big motsa ball hanging out there." George: "I just want to say it once. Everyone else gets to say it. Why can't I say it?" Elaine: "What, you never said it?" George: "Once...to a dog. He licked himself and left the room."