If you have enough miles in each account book 2 different itineraries (one for you & one for your wife) -Round trip-from each account separately. Or you could book 2 different one ways & both be on the same itinerary using miles from one account each way. Transferring miles from one account to another is permitted, but a rip off in my book, unless you only need a few miles to have enough to obtain what you want for your partner.

Try to find saver fares as standard fares are double and not a very good use of your miles.

Good luck & have fun!!!