hide a special friend on facebook

These are her privacy settings, and not yours, for the most part. She needs to create a group with just you in it, and share things with that one-person group.

You would do the same, making a group with only her in.

You would both have to remember, every single time, to only share with those one-person groups. You'd keep most of your communications off walls and instead do them via private message.

Or you could just come clean and tell your wife.