There is nothing wrong for a husband and his wife in offering the congregational prayer together.
Question:
Is it valid to lead my wife in congregational prayer? How?
Answer:
All praise is due to Allah, the Lord of the Worlds, the Beneficent, the Merciful, the Master of the Day of Judgment.
There is nothing wrong for a husband and his wife in offering the congregational prayer together in such places where there is no much mosques where people offer the prayer.
It is not disliked for a man to pray in congregation with his wife alone. In fact, the basic reward of praying in congregation is attained in this way. It is better, for the man, to pray in congregation with his wife than alone if he misses congregational prayer in the mosque. [Radd Al-Muhtar]
Responding to your question, Sheikh Ahmad Al-Hijji Al-Kurdi, an expert in the Encyclopedia of Jurisprudence and a member of the Kuwaiti Ifta department of the Ministry of Awqaf and Islamic Affairs, states,
“There is no legal prohibition in doing that and the wife stands behind her husband.”
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Source: Islamic-Fatwa .com