Bin Laden's father had many wives, so many bid Laden became discussed with his father for Mohammad permitted a man only FOUR wives at any one time, not the number of wives bin Laden's father or many of the male members of the house of Saud have.
Bin Laden also required them to go through various military training, including an infantry course, where they carried AKs. All but his last wife were Collage educated (The last and youngest wife appears to have been a political marriage in regards to the war in Yemen).
Before he ordered the 9/11 attacks he told all of his four wives he had at that time, if they did NOT want to live in a cave, he would understand and divorce them and leave them go home. At least one (and if I remember right two) of his wives took him up on that offer.
Here is a biography of three of the above four women:
Khairiah Saber, also known as Umm Hamza (mother of Hamza). A child psychologist with a PhD in Islamic studies, she was reportedly Osama's favorite wife, and the most mature, being seven years his senior. She had only one child, a son. Though she had a frail constitution and was not beautiful, she was from "a wealthy and distinguished family," exuded a "regal quality," and "was deeply committed to the jihadi cause". News reports suggest that she was living in bin Laden's compound in Abbottabad, Pakistan at the time of bin Laden's death.
Siham Sabar, also known as Umm Khaled (mother of Khaled). A teacher of Arabic grammar, she kept her university job and commuted to Saudi Arabia during their time in Sudan. News reports suggest that she was living in bin Laden's compound in Abbottabad, Pakistan at the time of bin Laden's death.
Amal Ahmed al-Sadah. Osama's youngest wife, born 1981. Born Amal Ahmed Abdulfattah in Yemen, she married Osama in 2000. However, according to a Yemeni passport, she was born in 1987. The marriage between Amal al-Sadah and bin Laden was apparently part of a "political arrangement" between Osama and "an important Yemeni tribe, meant to boost al-Qaeda recruitment in Yemen". Amal al-Sadah was identified as living in the compound in Abbottabad, Pakistan at the time of bin Laden's death, along with Siham Sabar and Khairiah Sabar, the other two wives of bin Laden. She was injured in the calf in the raid. Osama commissioned Rashad Mohammed Saeed Ismael to choose the bride and arrange the marriage.
His two two wives asked for and obtain a divorce in 2001, just before 9/11:
Najwa Ghanhem (born 1960) a Syrian, also known as Umm Abdullah (mother of Abdullah). Najwa was "promised" in marriage to Osama. Bin Laden married her in 1974 in Latakia in northwestern Syria. After the birth of their first son, Abdullah, they moved from his mother's house to a building in the Al-Aziziyah district of Jeddah. She is the mother of Saad bin Laden, as well as at least 10 more children. She co-authored Growing Up bin Laden with her son Omar. She was the youngest and least educated of Osama's wives. Her children did not like life in Khartoum and even less life in Afghanistan. She left bin Laden around 2001, about the same time as his marriage to Amal al-Sadah. She returned to Syria and was last reported living in Latakia. Her father is the brother of Osama's mother, Hamida al-Attas (born Alia Ghanem).
Khadijah Sharif (born 1948) also known as Umm Ali (mother of Ali). She was a university lecturer who studied and worked in Saudi Arabia. Umm Ali bin Laden spent holidays in Khartoum, Sudan, where Osama later settled during his exile in the years 1991 to 1996. According to Wisal al Turabi, the wife of Sudan's ruler Hassan Turabi, Umm Ali taught Islam to some families in Riyadh, an upscale neighborhood in Khartoum. According to Abu Jandal, bin Laden's former chief bodyguard, while living in Sudan, Umm Ali asked Osama for a divorce because she said that she "could not continue to live in an austere way and in hardship".
http://en.wikipedia.org/wiki/Najwa_Ghanem