There is a way to get more than $500k exclusion on one house.

Bob and Carol married, bought a house, value grew millions over 10 years, and they divorced. They did not sell yet. They BOTH remain in the house with children. They each own 50% of the house.

Bob brings his girlfriend Alice into the house, she lives there over 2 years. They get married and Bob and Carol agree to sell. Carol's boyfriend Ted also moves in, but they don't get married.

Bob's half has over $500k of gain, and on his MFJ with Alice they exclude $500k. Only one needs to own house, but both must live there 24 months.

Carol has over $500k of gain, and she excludes $250k. Carol didn't marry Ted, so only $250k.