laws are cultural"
So if slavery and rape are part of your "cultural" law, Christians just have to be cool with that. And who came up with the slave trading "laws" in the first instance? Your God. Before he apparently changed his mind and made the previously moral, immoral. On the other hand, Jesus didn't seem to object to masters beating their slaves (Luke 12:47-48). Keeping slaves is evil and always has been. Beating them is even more despicable, and please don't equivocate about it being a parable. A bad analogy is a bad analogy. St Paul, the feminist, you're joking right? His writing is some of the most misogynist in the scriptures: 1 Cor 11:7-9, Eph 5:22-24, 1 Tim 2:11-15 etc. And as for a relationship where one party is under the threat of punishment and torture for the slightest dissent, well, there are shelters for women who are treated like that by their partners. Christianity Isn't a relationship, it's a servile cult where its members are reminded of their position by constant comparison with slaves and livestock. And Any belief system in which eternal torture is a moral response to anything is sick. If my wife said in writing or otherwise that torturing my kids for not having faith in me was ok, I would have her sectioned.
The difficult we do today; the impossible takes a little longer.