...of breastfeeding except that which splits the intestines while at the breast, and that was before weaning." (1)

This is a hasan sahih hadith.

The practice according to most of the people of knowledge among the Companions of the Prophet, peace and blessings be upon him, and others is that breastfeeding does not make [marriage] unlawful except what occurred within the first two years, and whatever occurred after the complete two years does not make anything unlawful.

Fatimah bint al-Mundhir ibn al-Zubayr ibn al-'Awwam, and she is the wife of Hisham ibn 'Urwah.

6 - Chapter: What has been reported regarding what removes the obligation of breastfeeding

1187 - Qutaybah narrated to us, saying: Hatim ibn Isma'il narrated to us, from Hisham ibn 'Urwah, from his father, from Hajjaj ibn Hajjaj al-Aslami, from his father, that he asked the Prophet, peace and blessings be upon him, saying: O Messenger of Allah, what removes from me the obligation of breastfeeding? He said: "A slave, male or female." (2)

This is a hasan sahih hadith.

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(1) A sahih hadith, narrated by Ibn Hibban (4224) and al-Tabarani in "al-Awsat" (7513).
(2) Its chain is plausible for hasan grading. Hajjaj ibn Hajjaj al-Aslami — none narrated from him except 'Urwah ibn al-Zubayr, and al-Bukhari in his "Tarikh" and Abu Hatim wrote about him without mentioning any disparagement or praise, while al-'Ijli and Ibn Hibban declared him trustworthy, and al-Dhahabi said in "al-Mizan": truthful. The rest of the chain's narrators are trustworthy.
It was also narrated by Abu Dawud (2064), al-Nasa'i in "al-Mujtaba" 6/108, and in "al-Kubra" (5483), and it is in "al-Musnad" (15733), and "Sahih Ibn Hibban" (4230) and (4231).