Not exactly. The process of merging ThankYou accounts does not cause points to expire in the same way as Sharing, but expiration is determined by the terms of product which is the source of the points.
Up until 2015 Citi's policy was that points expired 30 days after the card which generated them was closed. I do not remember if this was also true of points generated by a bank account.
In 2015 Citi seems to have changed this policy, but they have not explicitly announced it. Instead, the terms of ThankYou Rewards refer us the printed terms and conditions of each product. Perhaps you could read the documentation which will arrive with your wife's account, and let us know what it says about ThankYou Point expiration?
Is this a workable strategy:
Get TY premier card, earn 50k TY pts
Get TY prestige card, earn 50k TY pts
Spouse also applies/gets the two cards also for 100K total TY pts
Combine accounts (mine)
Combine accounts (spouse)
Close both TY prestige cards for AF refunds. (When would these points expire? do we know?)
Keep TY premier accounts open
Transfer all spousal TY points to my account.
Would I still be able to transfer TY pts out to KrisFlyer after closing prestige accounts?
How long would I have to spend/use the TY pts?