Michał Kleofas Ogiński was married twice. His first wife was Izabela Lasocka (1764–1852), the second, Marija de Néri (1778–1851).
Izabela and Michał Kleofas married on May 17, 1789 in a Brzeziny church (Poland). It was a year when Ogiński swiftly ascended the ladder of political career – he became known as an active polititian and received his first state awards.
Lasocka was the only daughter of Polish magnates: the Castellan of Gostyń and Voivode of Ciechanów Antoni Lasocki (circa 1727–1799) and Teresa Godlewska-Laskowska-Lasocka. Izabela and Michał Kleofas had two sons: Tadeusz Antoni Ogiński (1798–1844) and Francizsek Ksawery Ogiński (1801–1837), and also at least one daughter. A reference to his having a daughter is in a letter from his mother Paulina Szembek-Potocka-Łubieńska (1737–1798-01-20) written in 1792 in Guzów and now kept in the Lithuanian State History Archives, in which she expresses her concern and sympathy at his daughter‘s illness and gives advice on her treatment.
So far no other evidence has been discovered in regard to this daughter‘s fate. She likely died in infancy and was buried in the Corpus Christi (Ogiński) Chapel of the Church of St. Johns in Vilnius. As stipulated in Michał Kleofas‘ will, written in Vilnius on August 16, 1818, he wished to be buried in this chapel at the side of his uncle (probably, Francizsek Ksawery Stanissław Ogiński (1742–1814) and his two daughters.
It may be speculated that Izabela had more children in wedlock with Michał Kleofas, but they must have died young. However, no documents have been found yet that could confirm or disprove this guess.
The official divorce of Izabela and Michał Kleofas took place on March 16, 1804. Unofficially, this marriage had been broken as early as in 1802, when Ogiński began living with Maria de Néri, the widow of a GDL statesman and military leader, Samogitian magnate Kajetan Nagórski (1757–1802).
Written sources mention that the marriage of Izabela and Michał Kleofas Ogiński fell apart because the husband and the wife for a long time had been living separately. They also had property-related disagreements.
Maria de Néri was born in 1778 in Florence and died on September 21, 1851 in Pisa. She likely had origins from a famous Italian family, which had also produced St. Philip Néri (1515–1595), even though this has not yet been confirmed by documents. At the time when the recently widowed Maria started living with Ogiński, the Lithuanian nobility largely thought her to be of low birth and poor reputation. When Michał Kleofas became a senator of the Russian Empire, his wife was granted an aristocratic title and was now called Maria de Néri- Ogiński.
Maria was known for her sharp mind and resourcefulness; she took an excellent care of family finances, an ability that served her well in her marriage with Michał Kleofas, since according to written sources, he travelled a great deal and did not have time for business matters; moreover, he was a spendthrift. Maria helped her husband in managing the estates of Zalesye and Rietavas, their Vilnius palace, and other domestic business even when he still lived in Lithuania; when Ogiński went to live abroad, all this and in addition, raising children, fell solely on her shoulders.
After 1822, when Michał Kleofas lived in Florence, the spouses, despite not living together, maintained contacts – they constantly wrote to each other. This is testimonied by their extant letters, now kept in the Lithuanian State History Archives.
When living in Lithuania, Maria de Néri, both before and after 1822, the year when Michał Kleofas departed to Italia for good, mostly resided in Zalesye.
Michał Kleofas Ogiński and Maria de Néri are known to have had five children in wedlock: Amelia (1804–1858), Emma (1810–1871), Ida (1813-?), Ireneusz Kleofas (1808–1863), and Sofia (1807–?) who died in infancy. It is unclear, whether the couple had more children. Written sources mention about Maria‘s adulterous affairs and express doubts as to Oginski‘s paternity of all Maria‘s children born in this marriage; however, judging from his above-mentioned will, he took care of all the children born in the marriage with Maria and acknowledged them all as his own. He exchanged letters and maintained contacts with with all his children even in the last years of his life (1823–1833), when he lived in Florence.