Complex sentence: Cockacoeske's husband/boyfriend was first married to Unity Croshaw, an independent minded woman who left him for his adultery, and some of whose descendants were the Dandridges, related to Martha Washington.
Split into simpler sentences: Cockacoeske's husband/boyfriend was first married to Unity Croshaw, an independent-minded woman who left him for his adultery. Some of their descendants were the Dandridges, related to Martha Washington.