After 62 years, I understand why you can't say no ! Did I read correctly 62 ?
First, 64 to 32 is a huge unsurmontable problem. Second, unless you have purchased XP with multiple licences, if you can do only one installation. A single licence XP cannot be installed on a second computer. Third, I have never heard having two different operating systems, 64 being one. I don't think that they ever made XP 64 bit.
However I do understand your wife's desire for if I ever got a new machine and that my wife could not longer play her favorite games, I would be forsaken, even after 63 years.
I assume you now have Windows 7 ? What happened to the old machine with the games on it ?
I don't think that creating a new partition would work, and I don't know if an external hard disk would work.
Why on earth have you changed ? Never mind, I don't really want to know the answer may get me to cry.
Are your wife's games on CD's ?
P.S. The 60th must have been quite a party ! I still can't believe it ! And I bet your wife is a doll !