Imagine, if you will, what someone as stupid and impressionable as Michael would take away from this. Since he's an imbecile who thinks that the world revolves around him and since he doesn't want to be bossed around by the women he can't help but think of as being weak and useless, the clueless dumbass eventually expected Deanna to pack his suitcase for him on their honeymoon. Since she didn't immediately cave like she was 'supposed' to, the assclown deliberately underpacked so that he could make a big show of buying what she 'forgot' at inflated prices so as to make it clear what her job was.
Since she used it as an opportunity to buy clothes, it's sort of clear that Lynn has no idea how romance works. What should have been a magical time was instead the beginning round of the same sort of joyless relationship that John and Elly have. It's also a clue as to why she and John take all those holidays in the sun. Simply put, she has certain expectations of a honeymoon and wants to one day experience same while at the same time doing her damnedest to prevent the magic from happening because love is scary and sex is icky.