All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger.
The hadeeth which you mentioned was narrated by Imaam Ahmad and others, and Al-Haythami said in Majma’ Az-Zawaa'id, "It was narrated by Ahmad, and its men are trustworthy, but some of them are weak."
It appears that this hadeeth is weak, and it is not authentically reported from the Prophet because a group of scholars classified it as weak and objectionable. For instance, Shu‘ayb Al-Arna‘oot said when reviewing the Musnad, "Its chain of narrators is weak, because Shahr ibn Hawshab is weak, and the scholars criticized Sukayn ibn 'Abdul-'Azeez [who was another one of its narrators]."
Moreover, Al-Albaani classified this hadeeth as weak in As-Silsilah Adh-Da'eefah, and he ruled that it is Munkar (hadeeth related by weak narrator and which goes against an authentic hadeeth). He classified it as weak due to the narrator Shahr ibn Hawshab; he said, "This hadeeth is clearly objectionable in several parts of its context, and it is contrary to the authentic hadeeth which reads: 'He has two wives from Al-Hoor'…"
Also, Ibn Al-Qayyim was quoted to have ruled it as Munkar. His statement about it is in his book Haadi Al-Arwaah, where he said:
"The weakness of Shahr ibn Hawshab is well known, and the hadeeth is objectionable, as it contradicts authentic ahaadeeth, because someone who is of the length of sixty cubits is very unlikely to have a seat whose width is one mile. The hadeeth narrated by Al-Bukhaari and Muslim states that each person of the first group who will enter Paradise will have two wives of the houris, so how can the one in the lowest level have seventy-two? The least of the inhabitants of Paradise (in number) are the women of this world, so how can the person in the lowest level of Paradise have a group of them."
Allah knows best.