Is it permissible for a woman to pray behind her husband if he is praying sitting down?

If sitting in front of a worshipper does not distract or preoccupy him, then there is no objection to it. However, if it distracts him, then it is disliked. This is supported by the narration of Aisha, may Allah be pleased with her, that the Prophet, peace and blessings be upon him, used to pray while she was lying across between him and the Qibla. There is no harm in praying towards the back of a seated man who is conversing.