This approach isn't working for me. I cannot find the "detach person" option when I am viewing a person. I've got a son married to his father--crazy--and I cannot figure out how to remove the father from the "spouse" list. Interestingly, this error doesn't exist in my online tree. Deleting the father as a spouse was pretty straightforward there, but the change doesn't take hold in Family Tree Maker when I sync.