Just that really..
Have been reading a few threads recently on the subject of affairs and betrayal and have been thinking back to my own experience (my Ex H was on affair no. 2 when we split).
My instincts are top notch and I suspected he was infatuated /chasing after the OW before they had ever done anything. The result was that I threw myself into 'private detective' mode and tried everything I could to prove that what I was feeling was right. Going through his phone, credit card statements etc. My ex was the type who would lie and lie and lie until you presented him with absolute irrefutable proof, (despite how distressed I was), then and only then would he admit to anything (and even then, only as little as he could get away with. Truth by increments).
I did make myself quite ill in the process, at times I thought I was going mad because he just kept lying, but to me truth was everything and I literally couldn't help myself - I HAD to get to the bottom of it, no matter how painful.
By total contrast my ex SIL is married to his brother who has also had affairs /cheated. (I know this from my ex H who he had confided in.) She doesn't know about the affairs as such, but I remember one drunken conversation with her when she was unusually candid and said that if she was really honest she thought he had probably cheated in the past, that there were warning signs, but she 'couldn't go there' and didn't want to because she couldn't bear it and didn't want to upset the status quo.
Is there a case for burying your head in the sand? They are still together, apparently very happily so. They have been married now for over 25 years. I have no idea if he still cheats. But she made it clear that if she had suspicions or if there were signs that she would bury them and turn a blind eye because she loves her husband and children, loves her (very privileged) life and doesn't want that to change?