Actually, it's the third strip in the sequence and John is the one that talks about being replaced.
Panel 1: It's late at night and John has decided that when he goes, Elly should remarry. That's almost big of him but I think she's already decided that for herself.
Panel 2: Just for curiosity's sake, though, what kind of guy would she choose if things came to that.
Panel 3: The kind that doesn't spring this sort of stuff on her at two in the blessed AM.
Summary: We'll probably get the third strip later in the week. Tomorrow's strip will be the "How the hell did you end up with me?" one, though.
ETA: Forget strip number two. Strip number two is like RetConnie's marriage to Pete Landry; it never happened. That's because it shows RetJohn in a positive, sympathetic light. Instead, we'll see strips that confirm RevElly's right to not appreciate him in the least.