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”.
P.S. I’m sorry I misspelled your name above, LouGoode. I’d first spelled it “LouGoodes”. Then when I deleted the “s”, I accidentally also deleted the “e”. And now, the software doesn’t let me go back to fix it.