I'll refer you back to my previous post...
The other thing is that trust is obviously important in a relationship but where something is happening to erode that trust, it would be foolish to ignore it on the basis of what is a relationship without trust?
It's still important to 'affair proof' a relationship as much as possible.
And sometimes people know they are pushing boundaries but think their spouse doesn't care because they've never said anything. At the moment, maybe he's thinking all of it is OK because you haven't told him it's not. After all, he's not hiding anything from you at the moment. But an opportunity is definitely being created.
Another one from my extensive experience... I have a friend who is slightly younger than me who isn't having a great time in her marriage at the moment. We sometimes go out for a drink and her relationship troubles are often mentioned. Sometimes, my partner comes with us. No problem. she and he get on and they like each other. But... she becomes very flirty when he is around. She'll hug/kiss him on arrival/departure and place a hand excitedly.on his arm when talking to him. Her eyes sparkle when he talks tp her. I see none of that when she is just with me or other friends!
I don't think she is interested in him really but she clearly enjoys the time away from her own life and it's current problems and lighthearted conversations with/attention from another man.
I haven't said a word to him.but he has obviously noticed this because he no longer makes himself.available for the hug/kiss and he no longer sits close enough to her for her to touch his arm. She has an allotment. He would love one. I have zero interest. She has invited him to her allotment. To see it. To help on it. Suggested he can grow stuff on the allotment... he has turned down every invitation.