"Writing at a time when divorce was permitted only in cases of adultery, he took the radical position of emphasizing spiritual compatibility. If a man and woman did not get along, Milton argued, then their relationship undermined God’s reason for creating matrimony. A marriage between two incompatible people was not, according to Milton, a marriage at all."

Stephen B. Dobranski. “Milton’s social life.” The Cambridge Companion to Milton, ed. Dennis Danielson, pp. 11-12.