If you are not afraid to have unprotected sex with your wife, you should not be afraid of her feces.
If you are in a long term sexual relationship with your wife (most married men are), and if she is very healthy, I believe she can be a donor without taking any blood tests.
I believe those donor criteria on curezone are for people who have no possibility to do blood tests, and for people who are not in a long term sexual relationship. If testing blood and feces of a donor is not an option, and if a donor you chose is almost a stranger, than you would probably like to choose a donor based on the most strict criteria, to decrease any chances of getting an infection.
People who are in a long term sexual relationship and live together have already exchanged both blood, saliva and almost any other bodily fluids, so FMT is really not as a high risk. Most criteria are to diminish risk factor for contracting some unknown blood born disease (HIV, HEPATITIS C, HEPATITIS B,A, HPV, HSV1, HSV2, Chlamidia, STDs, etc ).
If you live in a western country, and you can afford a stool test, it could be smart to test her feces for the presence of all possible bacteria, and how it compares to others.