You cannot accrue miles to an account for the person who pays only for the person who travels. However, there are programs which are flexible. For example Alaska allows you to transfer miles from one account to another. BA has family plans, whereby all accounts of a family can be pooled to obtain awards.
If you have currently no AsiaMiles, it might be worth considering as CX is part of both programs (just like AA, BA and many OW airlines are part of Alaska FFP). If you already have a significant amount of miles, that might not be a great idea if your wife seldom flies.