Dups - Name Data Merging?

I'm new here, so please excuse me if this has already been discussed.  When you have duplicate records and one has only the wife's name (the record to be "kept") and the other has husband and wife's names (the record to be "deleted") and you schedule a merge, why is the husband's name NOT merged into the "kept" record?  The logical conclusion for a merge of duplicate records is that all "unique" information will end up in the "kept" record, yet I am not seeing this happen.  Can anyone explain if (a) I'm doing something wrong, or (b) if this is a software glitch that needs to be rectified?

Bonny, Colorado Ballet