Scripturally, neither the husband nor the wife has the power or right to make theirs an “open marriage”. Scripturally, God created marriage, and he didn’t offer an “open marriage” option. Either marriage mate can forgive the other’s adultery and stay with that mate, but no human has the power to make adultery “not a sin”.
I'm going to disagree with you. The religions created marriage not God. Ancient Israel practiced polygamy for centuries along with any number of other civilizations. Sin is defined as a transgression against divine law, but the problem is nobody has ever been able to spell out what is and what isn't a divine law. If a couple together decide they are okay with an open marriage, then it is between them. It is not the business of any church to decide. That said, the honorable thing to do if either partner decide an open marriage isn't for them is end the marriage or remain faithful.
As for Lloyd in addition to betraying Dijana, he decided his infidelity should include using an industry that is known for trafficking women and minors. That is far more disgusting than simply being unfaithful. What makes this decision even worse is his pretending to be an advocate for the sexually abused. The man simply has no honor.