He leaves the kitchen in a mess. When he changes clothes, he drops them on the floor.
(中略)I don't want to nag, but I also don't want to be his maid. Any suggestions?
Auntyの回答の出だしは次ぎのようになっていました。
Dear Neatnik,
You're neat; he's a slob. This setup has made for many happy unions. (I happen to know of slobs married to neatniks.)
"neatnik" は "a person who is extremely neat about surroundings, appearance, etc." で "slob" はその反対の性格の人間である事は容易に分かります。また "neatnik" は昔 "beatnik" (a member of the Beat Generation; a person who rejects or avoids conventional behavior, dress, etc. )なる言葉が流行っていた事を思い出します。
"slob" も初めて見る単語ではないような気がしますが、この単語だけで出てきた場合には意味が直ぐ頭に浮かばないので辞書を引きます。
OneLook Quick Definitions: a coarse obnoxious person
Dictionary.com: a slovenly or boorish person.
かえって難しい単語が出てきたのでもっと易しい説明を探します。
Cambridge Advanced Learner's English Dictionary: a lazy, untidy and often rude person: He's a big fat slob of a man - I can't stand him.
Webster's New World College Dictionary: a sloppy, coarse, or gross person
これで安心して納得できます。 問題は憶えられるかですが。