Abdullah bin Abbas reported,

One morning we awoke to find the wives of the Prophet ﷺ weeping, with the family of each woman gathered around her. I went out to the mosque and found it filled with people. Then Umar bin Khattab came and went up to the Prophet ﷺ, who was in an upper chamber of his. He greeted him with salam, but no one answered. He greeted him again, and no one answered. He greeted him a third time, and still no one answered. So he called out to him and was admitted to the Prophet ﷺ.Umar asked, "Have you divorced your wives?"The Prophet ﷺ replied, "No, but I have sworn to keep away from them for a month."He remained apart from them for twenty-nine days, then went in to his wives.

Azami 4329

Sahih

عن ابن عباس قال

أصحبنا يوما ونساء النبي ﷺ يبكين، عند كل امرأة منهن أهلها، فخرجت إلى المسجد فإذا هو ملآن من الناس، فجاء عمر بن الخطاب فصعد إلى النبي ﷺ وهو في غرفة له، فسلم فلم يجبه أحد، ثم سلم فلم يجبه أحد، ثم سلم فلم يجبه أحد، فناداه، فدخل على النبي ﷺ فقال: أطلقت نساءك؟ فقال: لا؛ ولكن آليت منهن شهرا فمكث تسعا وعشرين ثم دخل على نسائه.

الأعظمي 4329صحيح
Contents
Reference
Commentary
Ayat
Collection
Jami al-Kamil
Book
Fasting
Chapter
Obligation of fasting, its virtue, and its rulings
Section
Month can be twenty-nine days
Numbering
Jami al-Kamil 4329 (2nd edition)
Azami 4329