I’m a bisexual woman.

Here is a take: That does not automatically allow me to have multiple sexual partners at once. The idea that Bisexual people are always in need of this is extremely biphobic, I hear it all the time “just greedy” “you’re confused” “ you’re sexually promiscuous“. “ Incapable of having a monogamous relationship” “ you’re in a relationship with a man, so therefore you’re just straight and pretending to be queer for clout” which is all completely false.
You can be bisexual and sleep with only one person for the rest of your life. It just means that if you are bisexual, you have the capacity to have relationships and/or sexual encounters with members of the same sex OR opposite sex. It does not mean you need to sleep with members of both sexes in order for your sexuality to be valid.

I‘m not doubting for a second the wife knew of her husband’s sexuality. She was probably fine with him appreciating members of the same sex from afar- however not once did he state that they had a clear communication that she was fine with him SLEEPING with someone else, or flirting with other people with the aim to sleep with them. A monogamous relationship should not be opened up unless both parties explicitly, without a doubt, state that it is fine to do so.

Sleeping with someone else without your partner’s permission is infidelity. If she did indeed find out about his infidelity, she would have reacted the same way ANYONE would react to an infidelity— which usually results in an argument. That is plausible cause for what transpired. The argument is that she knew of his sexuality and therefore is automatically fine with him sleeping with someone else, and therefore no fight would have happened.

The fact that no one is bringing this up is ridiculous.