If a husband and a wife are praying at the ends of the room, then should the wife still stand a little behind the 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 pray behind the man. Anas reported: "An orphan and I prayed behind the Messenger of Allaah and my mother (or grandmother) prayed behind us (forming a row by herself)." [Al-Bukhari and Muslim] The standing of a woman behind a man is not an obligation and is not a condition for the validity of her prayer according to the most preponderant opinion of the scholars. Therefore, her prayer is valid even if she prays standing next to her husband, if there is no space, but it is best to stick to the Sunnah.

Allaah knows best.