GA is absolutely correct. You also run the risk of catching an STI. The only thing I can suggest is telling her that if she will stop seeing the klaus, you will be happy to spank her etc - assuming you would enjoy playing that role.
But, she could end up dead, these people don't know when to stop. Her career will go downhill, and she will regret it. She may have well singed a contract, but she signed a marriage contract with you prior to that. The rules of open relationships are: there must be no emotional involvement. She is being stupid.
If you are broad minded, you could even say that you were OK with what she was dong with her workmates, but this new development has crossed the line. If it were me, I would insist on divorce if she does not cool it with him.
The other thing you did wrong was to tell her you did not want to know details. If you are skilful, you can get her back on side bit by bit. But you have to realise that she has lost her mind. You are going to have to pull out all the stops. As a last resort, if she won't listen - the threat of losing custody of her kids might be the final sanction, but let's hope you don't get that far.
This is why my wife and I aren't swinging - we don't need the chaos. But as a fantasy it's great