The hadith says, "Prophet's wife Ayesha" used to visit the graves of her husband (Prophet PBUH) and his father Aboobacker (Razhiallahu Anhu) without veil. But after Umar (Razhiallahu Anhu)'s death, he used to wear full veil while visiting the graves stating that there is another man (Umar) who is not mahram to her in the grave. This is the Takwa (Fear to God) of women and they follow this for themselves to get the satisfaction of Allah.
The hadith says, "Prophet's wife Ayesha" used to visit the graves of her husband (Prophet PBUH) and his father Aboobacker (Razhiallahu Anhu) without veil. But after Umar (Razhiallahu Anhu)'s death, he used to wear full veil while visiting the graves stating that there is another man (Umar) who is not mahram to her in the grave. This is the Takwa (Fear to God) of women and they follow this for themselves to get the satisfaction of Allah.