It's not the kind of lifestyle I'd want for me (at least, I don't think I would want this), but you guys would be surprised what people tolerate to keep a marriage. I've known two husbands to give their wives permission to have sex with another guy (ironically, both of the other guys were friends of these men). Also, a very close friend suspected for years that her husband had a girl on the side, but she overlooked it because she didn't want to tear her kids family apart. In all these cases, the extra relationships eventually ended on their own.