Lincoln and Marriage

On p. 255 of Harry Jaffa's A New Birth of Freedom, Jaffa quotes Lincoln from his Indianapolis speech February 11, 1861:

[For the Southern states] the means for the preservation of the Union...is of a very thin and airy character...In their view, the Union, as a family relation, would not be anything like a regular marriage at all, but only a sort of free-love arrangement, to be maintained by what that sect calls passionate attraction.