Anas ibn Maalik (R) narrated that the Messenger of Allah (S) said: 
whoever Allaah blesses with a righteous wife, then He has assisted him in half of his deen. So therefore, let him fear Allaah in the other half. (Al-Mustadrak: 10/2681) Al-Albaanee declared the hadeeth hasan in Saheeh At-Targheeb (1916)

Al-Manaawee’s  explanation of this hadith:
‘That is because the greatest trial that takes a significant toll on a person’s deen are the desires of the stomach and the desires of the private parts, and a righteous woman safeguards a man from zinaa, which accounts for the first half. Hence, the second half remains and that is the desires of the stomach. Thus he (S) advised him with taqwaa so he can perfect his deen and obtain istiqaamah (be upright and obedient).’ He also said, “He (S) specifically mentioned a righteous wife because a woman who is otherwise may safeguard her husband from zinaa, however she would make him bend his back over trying to obtain worthless things from that which is haraam.” (Al-Faydul-Qadeer: hadeeth nos. 8704)