If your wife doesn't ride much, don't give her cleats. Just let her use so-called platform pedals. They're fine.

My wife can use toe clips just fine, but she recently decided to do away with them. Nothing wrong with that. She tried cleats and didn't like them at all and won't try them again. She cracked her elbow. Even though a recurrence is not likely, she just doesn't want to take the chance.