Hafsah Bint ‘Umar 
was born five years before the Messenger of Allaah 
became a Prophet. She was six years older than her brother ‘Abdullaah 
. She was a beautiful and pious woman.
Her first marriage was to Khunays Ibn Huthaafah Ibn Qays as-Sahami who was from Quraysh. He took part in the two emigrations (to Abyssinia and Al-Madeenah). He fought in the battles of Badr and Uhud. In the latter battle he was fatally wounded and died shortly thereafter in Al-Madeenah. Hafsah was 18 years old at that time.
‘Umar was depressed because of his daughter’s affliction, since she had become a widow at such a young age. Whenever he went home and saw his sad daughter, he grieved. After thinking for a long period, he decided to choose a husband for her, to provide her with what she had lost of repose for six months or more.
‘Umar approached Abu Bakr the dearest person to the Prophet and offered her hand in marriage to him.
‘Umar thought that Abu Bakr would not refuse to marry a young, pious woman who was the daughter of the man by whom Allaah supported Islam. Having sympathetically listened to him, Abu Bakr did not respond.
‘Umar went back with a broken heart and almost did not believe what had happened. He then went to ‘Uthmaan Ibn ‘Affaan whose wife, Ruqayyah the daughter of the Prophet had recently died.
‘Umar offered him his daughter in marriage, but ‘Uthmaan apologized by saying: “I think I would not like to marry at the present time.”
‘Umar’s gloom increased by ‘Uthmaan’s refusal. He became upset and angry with his two companions, mentioning it to the Prophet complaining about Abu Bakr and ‘Uthmaan 
.
Thereupon the Prophet smiled and said: “Hafsah will get a husband who is better than ‘Uthmaan and ‘Uthmaan will get a wife better than Hafsah.” [Al-Bukhaari]
After that, the Prophet himself married Hafsah and ‘Uthmaan in turn married Umm Kulthoom, the Prophet ‘s other daughter .
Accordingly, ‘Umar was elated to receive such a great honor which he had never imagined possible, earlier. He went off to tell the good news to whomever he met.
When Abu Bakr met him, he realized the source of his joy. ‘Umar told him of his unhappiness at Abu Bakr’s refusal to reply when he had offered Hafsah’s hand to him.
Abu Bakr congratulated him and apologized by saying: “Do not be angry with me, ‘Umar, the Prophet mentioned Hafsah before, and I could not disclose the secret of the Prophet . Had he left her, I would have married her.”
Since the Prophet had mentioned Hafsah to him, he did not want to disclose the Prophet’s ‘s secret.
The people of Al-Madeenah were pleased with the Prophet’s marriage to Hafsah Bint ‘Umar . It was contracted in the month of Sha’baan in the 3rd year of Hijrah.
Thus, Hafsah joined the rank of the pure wives of the Prophet the Mothers of the Believers, who were by then, Sawdah and ‘Aa’ishah ; and became a member of the household of the Prophet .
Sawdah was happy to see her but ‘Aa’ishah, may Allaah be please with her, was upset because Hafsah was within her age group and she feared that Hafsah would share the love of the Prophet .
‘Umar knew very well that the Prophet loved ‘Aa’ishah more than any of the other wives and at times tried to make his daughter aware of this fact. He once said to her: “You are not like ‘Aa’ishah and your father is not like her father.”
When the Prophet deserted his wives because they became too demanding, ‘Umar once again advised Hafsah to be careful saying: “You should not be deceived by the one who has been motivated by her beauty and the love of the Prophet for her (referring to ‘Aa’ishah).”
When the Prophet married his other wives ‘Aa’ishah began to realize that her protestations were in vain and she made a friend of Hafsah .
Among the other wives of the Prophet ’Aa’ishah was the most intimate and the closest one to Hafsah . It was Hafsah and ‘Aa’ishah who supported each other against the Prophet in a domestic intrigue which is mentioned in the Quran.
It is also mentioned in a tradition reported in the book of Imaam Al-Bukhaari 
:
‘Aa’ishah narrated: “Allaah’s Messenger used to drink honey in the house of Zaynab Bint Jahsh and would stay there with her. So Hafsah and I agreed secretly that if he comes to either of us she would say to him: ‘It seems you have eaten Maghaafir (a kind of flower whose nectar is sucked by the honey bee, and has slightly bad smell) for I smell in you the smell of Maghaafir,’ (we did so) and he replied: ‘No, but I was drinking honey in the house of Zaynab, the daughter of Jahsh, and I shall never take it again. I have taken an oath as to that, and you should not tell anybody about it.’” [Al-Bukhaari]
The idea was to suggest to him that this bad smell came from his mouth because of his taking that particular honey.
The Prophet has always disliked strong smells especially on his breath. He then forbade honey unto himself for which Allaah revealed (what means): “O Prophet, why do you prohibit (yourself from) what Allaah has made lawful for you, seeking the approval of your wives? And Allaah is Forgiving and Merciful. Allaah has already ordained for you (Muslims) the dissolution of your oaths. And Allaah is your Protector, and He is The Knowing, The Wise.” [Quran 66: 1-2]