"You shall not covet your neighbour's house; you shall not covet your neighbour's wife, nor his male servant, nor his female servant, nor his ox, nor his donkey, nor anything that is your neighbour's," the 10th commandment, Exodus: 20:17 (New King James Version)
Of all the bro codes, the worst that you can break is to have sex with your best friend's wife. If you are shot dead, if your legs are cut, or if your penis is severed, you deserve it. The woman deserves as much punishment.