He attempts to keep it private, even from his family, even, in fact, from the family that the relationship begets. He gives his white family his love, his black family their freedom. Theirs is a lie, founded in love. Half the black family uses its freedom to escape the grasp of history altogether. The other half uses it to claim its rightful inheritance, which is to say, a heritage, a connection to history itself.
Subsequent generations take sides.
A family quarrel becomes a national one as well. These are the things we do for love.