And that covenant is what sets apart the whore and the concubine.

Both are disposable and there is no loyalty there, nor requirement to love, or to have reverence. They are primarially agreements of convienence.

There's a ton of scriptural examples as well for this, very notably Abraham himself in Gen25. Abraham had a wife, but also apparently a several concubines, and he paid them so they would leave and not interfere with the inheritance he gave to his son Issac. He didn't really care about the concubines and any kids he had with them. They were live-in girlfriends out of convenience, but not a wife.

So so so many examples in the Bible how the Holy Ghost (the narrator of the Bible) in no way considers mere sex to be akin to marriage.