This type of rate is rarely a good deal for more than a one night stay....but then - do you really want a spa treatment every day? I wouldn't, and I "love to spa"! You also need to check the actual spa packages that aren't involved with a room rate - sometimes the published room/spa combo is more costly than purchasing separately.
what we do -
1) book the first night at the special rate on one name -get the bennies. if you REALLY want more spa treatments, book the 2nd night in your wife's name - and take it up with the front desk about not changing rooms on the 2nd day.
2) book the rest of the nights using whatever best rate you can get - and if it is more than 2, try to find a rate on which a BB or PP will apply.
3) use the money saved via the BB or PP to either buy another spa treatment or (whatever else) you might like.
also see PM -