Pretty sure almost all my friends have cheated at one point or another, consistently or just once or twice
This was 15 years ago, but I remember having a hotel suite for my birthday, and my boy did some Goodfellas shyt and brought his girl on the side on Friday and his wife the next day, two sets of couples. That's really not my business though. He stopped all that years ago and raised a family and stayed with his wife.
One of my other boys was serially unfaithful, but I got tight with both his new girl, and her sister, never told anyone anything until it was all done between them.
It makes sense for some people, that see marriage/coupledom as a shared value to protect, but for me, it's not really my place to 'check' them, I might comment on it, clown them, point out their bullshyt, but it's not a wedge issue in the friendship.
One of them once said "i never cheated on her once" and was feeling sorry for himself, so I named like 6 times I remembered, in different hotel rooms where I was present lol