It is not really a mess at all when it is understood how the New Testament supersedes the Old, and the Old can only exist within a relativistic historical context. Revelation was progressive.

It is also the case that we Orthodox view much of the content of the OT to be highly symbolic, each passage having a variety of meanings, some of which are only historical in nature with the moral truth disclosed more discretely.

I don’t interpret this new passage the same as you, it clearly says the believers can’t leave their partner, only the unbelievers can, that’s not liberty.

This is about religious practice, though - it has nothing to do with liberty as it concerns the non-believer.

Being a believer means acknowledging a higher truth than oneself and shaping one’s life after it.