Was there a text stating the delay of marital relations until the seventh day, and what are the books that discuss the life of the Prophet, may Allah bless him and grant him peace, with his wives?

There is no evidence for the desirability of delaying sexual intimacy between spouses until the seventh day. To learn about the life of the Prophet, peace and blessings be upon him, with his wives, one can refer to biographical works such as "Zad al-Ma'ad" by Ibn Qayyim al-Jawziyya. One can also benefit from specialized books on marital relations such as "Tuhfat al-Arus," "Al-Liqa' bayna al-Zawjayn," and "Mutat al-Hayat al-Zawjiyyah."