Marriage to David Ben-Gurion
On 5 December 1917, Munweis and Ben-Gurion married each other in a civil ceremony at the New York City Hall. This surprised Ben-Gurion's fellow activists, who did not even know he and Munweis were in a relationship. They refused to seek sanctification for their marriage from a rabbi, despite repeated pleas by religious officials throughout their life together. Understanding that they did not share each others' views on Zionism, Ben-Gurion had warned her that, if they married, she would have to move with him to Palestine, which at the time was a poor country without modern public utilities. He also told her that he planned to enlist in the nascent Jewish Legion and fight in the Palestine campaign against the Ottoman Empire. She decided to marry him anyway, hoping she would be able to dissuade him from going to Palestine and signing up to the Legion. Munweis took her husband's surname, Ben-Gurion. She also began using Paula as her first name, going by what her husband called her. Before long, she had given up her career as a nurse to commit to married life. She left the Beth Israel hospital, two months before she was due to graduate with her diploma, despite pleas from her friends. According to Israeli historian Anita Shapira, "she made him her life's work". Shapira wrote that Paula was not an intellectual or emotional partner for Ben-Gurion, and instead dedicated herself to caring for him. She introduced him to personal hygiene practices such as regularly bathing, brushing his teeth and even changing his underwear, which he had previously been unaccustomed to.
In April 1918, after only five months of marriage, Ben-Gurion informed Paula that he had enlisted in the Legion and was about to be deployed to Palestine. Paula, having just found out that she was pregnant, broke down in tears; she would have to give birth and raise their child alone. She tried to convince him not to leave, but he responded that he believed his cause was "greater and more sacred than anything in the world", including her. Left alone while waiting for their first child, she became severely depressed. In his letters to her from the front, he took responsibility for having left her and reaffirmed his love for her, but continued to justify his actions, believing that his Zionist ideals would eventually bring them "divine happiness" and "uninhibited love". He wrote to her that, if he had not enlisted, then he believed he would have been "unworthy of you bearing my child". On 11 September 1918, Paula gave birth to their daughter; following her husband's wishes, she named her Geula (the Hebrew word for "Redemption"). She wrote that their baby was pretty, despite resembling her father.
A year after the war ended, Paula finally reunited with her husband in Palestine. She had agreed to emigrate purely out of obligation to her husband. She insisted on travelling first class, and after a six-week journey, she and her daughter arrived in November 1919. The family then travelled to London, where Paula gave birth to a son; they named him Amos, after the Jewish prophet. They then moved to the Polish city of Płońsk, where they stayed with Ben-Gurion's family for over a year while Ben-Gurion himself travelled around for conferences. Paula had a tense relationship with her in-laws, frequently criticising their poor hygiene. She also struggled with the poor standard of living in the city, having to boil the contaminated municipal water. In 1925, she gave birth to their third child, another daughter, who they named Renana. Paula refused to bear him a fourth child, despite his desire for another. By then, their relationship had deteriorated; Ben-Gurion spent much of his time away from home and communicated with Paula in an increasingly formal manner, expressing less affection towards her. Many of his letters to her were not intended to be kept private, and some were specifically intended for people other than her to read. According to British historian Elizabeth Monroe, "Paula [was] a mere shadow" in Ben-Gurion's correspondence during this period.
In the early 1930s, the family moved into a newly-built house in Tel Aviv. They all stayed in a single room, while Paula rented the other rooms out to families on holiday in the city. In May 1935, Paula discovered that, over the previous four years, her husband had been having an affair with a woman named Rega Klapholz during his trips to Europe; she forced him to end the relationship after Klapholz arrived in Palestine. In August 1935, Paula was delegated to the Nineteenth Zionist Congress in Lucerne; she set sail along with Rachel Yanait Ben-Zvi, Dov Hoz, Abba Hushi, Berl Katznelson, Golda Meir and David Remez, with whom she spearheaded an initiative to establish a shipping company under the Jewish Agency. Following the congress, Paula and her husband settled in rural Switzerland. Her husband attempted to reconcile with her, but she did not enjoy the location as much as him and did not join him on his walks through the mountains. In August 1937, Paula attended the Twentieth Zionist Congress in Basel, where she clashed with Chaim Weizmann over his disrespect towards her husband. By the late 1930s, Paula shared her husband's interests in their correspondence with each other.
Following the outbreak of World War II and the Battle of France in 1940, Paula's husband wrote to her of his hope in the governments of Britain and the United States to win the war against Nazi Germany. He frequently praised British prime minister Winston Churchill in his letters to her during this period. During the war, Paula's son Amos was wounded while serving in the Jewish Brigade and was hospitalised in Liverpool, where he fell in love with a Manx nurse. Paula objected to her son marrying a gentile and attempted to pressure him not to go through with it, but the wedding went ahead despite her protests in 1946. Paula was incensed when her husband welcomed their new daughter-in-law into the family and helped her emigrate to Palestine.