Why did the Messenger order the couple to bathe together?

The answer is:  For what this commandment instills in their hearts of affection and love

The Prophet Muhammad, may God bless him and grant him peace, ordered the couple to take a bath for several reasons. He wanted to increase the marital relationship between spouses and avoid potential problems, as well as help strengthen the intimate relationship between them. Furthermore, the Prophet Muhammad reportedly recommended that couples take a bath together, especially immediately after intercourse. This is because bathing together can create an atmosphere of trust between spouses, whereby the wife feels secure in her physical ability when she is fully exposed to her husband, unlike sexual intercourse. Thus, taking a shower together can foster an atmosphere of mutual trust and love, which is beneficial for both spouses.