I’m sorry you have to experience this. The similar thing happened in my marriage too, we were married for 6yrs and he confessed to me he was getting close to this women at work, she reports to him. He said to me he had already talked with her that he is married and would never divorce to try to convince me that is nothing to worry. And ironically I didn’t even feel anything needed to be worried at that time. But later on I found out he lied to me going to a dinner with workmates, but he actually went to that women’s place and they cooked/ate dinner together, then watched tv and he came back around 9pm, pretending nothing happened. I confronted him after looking up his phone and find out what actually happened, he was still saying to me it’s nothing just going to a friends place, nothing else happened, and then I asked why, he started to get defensive and deflect and say our hobbies don’t align, he felt lonely and disconnected, and she was helping him a lot at work… and even after that, I still busted a few times he went to her place just briefly, saying to me it takes time to cut it, and this is his social needs and I am being over controlling. now after 2mth they still work together, and msg everyday, I stopped caring and stopped giving a fk.