It is perfectly fine for husband and wife to pray taraaweeh even as they are allowed to pray all other prayers in congregation-- if they cannot, for one reason or another, make it to the mosque, although we can never exaggerate the importance of praying in the mosque, especially the five obligatory prayers.

While husband and wife are praying together, it is not always a must that the husband leads, especially if the wife is more qualified to lead. It is ok for her to lead. We have a precedent for this in Umm Waraqah who was appointed to lead members of her household in prayer. Umm Waraqah was one of those few women who excelled in retaining the Qur’an; hence Prophet, peace be upon him, appointed her to lead the salah at home. Furthermore, we are also told that the Prophet, peace be upon him, appointed an elderly person (of her own household) to call adhaan for her. Based on this, there is no harm in wife leading, especially if she is exceptionally qualified to do so.