He, sallallaahu ‘alayhi wa sallam, would pay attention to his personal hygiene and smell:

The Messenger of Allah, sallallaahu ‘alayhi wa sallam, would use the tooth stick (Siwaak) to clean his teeth as soon as he entered his house so that his wife would not smell a bad odor from his mouth.

Shurayh ibn Haan’i (a Follower belonging to the generation succeeding the Companions) narrated that he asked ‘Aa’ishah, “What was the first thing the Prophet of Allah, sallallaahu ‘alayhi wa sallam, would do when he entered the house?” She said: “Clean his teeth with a Siwaak.”

As-Suyooti (a scholar) said: “The wisdom behind this is that his mouth smell might have changed after talking to people all day, and thus he, sallallaahu ‘alayhi wa sallam, was keen on removing any odor as a way of being extra nice and kind in his treatment to his wives.