Can a husband and wife pray side by side or should a wife pray behind her husband?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

The Sunnah is that the woman should stand behind the Imaam in prayer even if it is her husband. She should not stand to his right or left side, and this is agreed upon among the scholars of the four schools. The evidence about this is the narration of Al-Bukhari and Muslim that the Prophet led the prayer with Anas Ibn Maalik and his mother Um Saleem . Anas said: 'I and an orphan stood behind the Prophet and the lady (my mother) stood behind us.'  Um Sulaym was the mother of Anas, yet she did not stand next to him (by his side) during prayer, rather she stood behind him. So this is an evidence that a woman should not stand next to a man in prayer.

Allaah knows best.