Which is not moral progress.

While the detail of your arguments don't follow I do agree that enforcing moral values from our time onto another time without taking care to first change all sorts of other parts of the culture would make the selected change we call "progress" actually do significant damage to the people we force our values upon.

Being able to consider the issue of once-off vs ongoing consent to sex to be the particularly significant issue regarding marriage morality is something of a luxury. Compare this to the issue of easy no-fault divorce... which can translate to "the ability to casually destroy the life of the divorced (female) party, leaving her to starve or be forced into prostitution". This is another thing that I recall Paul speaking on and something far more controversial at the time.

It can be dangerous (and naive) to try to judge or force our values on other cultures without thinking through the effects such changes would have.

But as Saint Paul rather delicately said, and people in the eighteenth century rather more plainly said, enforced abstinence is not going to fly.

Yeah, in certain circumstances people are going to have incentives to break promises (and/or contracts). I don't think that this is specific to marriage, and I don't think it makes the concept of marriage invalid.