* FridgeLogic: There was no reason why he couldn't tell his wife about the clones.
** She might very well have freaked out at the least. Of course, keeping it from her means that she essentially had sex with identical twins of his without ever knowing it.
* UnfortunateImplications: The whole premise of the movie is that it takes four men to please one woman, and even then they don't quite get it right.
** Alternatively, the moral might be don't try to fix your problems with quick solutions. Doug thinks at first that delegating his responsibilities would make his life easier: it doesn't and in fact he gets more estranged from his family and what he actually wants. He gets a lot of work done because HE thinks his wife wants more luxury but he never actually listens to her; she wants to work not because of the money (even though they are in a kind of tight financial situation, because neither plans things ahead of time) but because of self realization. And in the end Doug realizes this and his procrastination with stuff related to his family is the actual problem, so in a sense he goes and fixes things. And his wife is plenty pleased sexually; so maybe the other moral is sex isn't everything in a marriage?
** Another problem is his wife having sex with his clones-essentially the ultimate BedTrick, though none of the parties actually planned it that way.