Living together, sex, and having children are things common to people who “hook up” for periods lasting anywhere from a week to a few years.
Clearly what is important is intent. In Matthew 19, the Pharisees tempt Jesus with the question, “‘Why then did Moses command to give a bill of divorcement, and to put her away?’
8. He saith unto them, Moses for your hardness of heart suffered you to put away your wives: but from the beginning it hath not been so.”
They were splitting hairs with the Lord, like a bunch of lawyers, trying to maneuver him into a corner. But he made it clear. God puts up with our machinations because of our hardness of heart.
The fact that God allows us to violate his ordinance should not be seen as consent.