It was just a matter of days for my (then) wife. As best I can recall, it was likely around 3 days, give or take 1 day.
I have no idea who made the suggestion or how circumstances were arranged.
As I remember it, I had chosen to stay home on a Monday night to watch football. She said she was going to my boss and his wife's apartment, and left our apartment in a huff. She called a couple or so hours later, and when I answered the phone, she said "Guess what I'm doing right now?"
It was easy to tell she meant "I'm getting fucked right now", so I told her that was my guess. She said that she wasn't, but she was at a former boyfriend's house, and was posing for pictures in her panties for him. She went on to say he had pictures of her sister ("he's fucked her, too!"), and he had many, many pictures of girls in their panties on his wall, and she was going to be added to his collection.
Now, it's not anything I wanted her to do, and I didn't actually know the first word about cuckoldry at that time, so it's hard to label it as such. But it was a display of her power, and she was making it clear she was in control of her pussy. Married or not, she would give it to anybody she chose, when she chose, and she did just that!
I will assure you she was totally satisfied with her decisions. I wasn't, but much like xxjibxx, I learned to live with it, if not enjoyed it.