Buyers Beware: The initiating motives and objectives of cuckolding are usually very different between males & females. Usually with males, they're satisfying a desire, but with females they're usually satisfying a need.
If I was a married man who's wife initiated the discussion to let her see other men, I'd be very concerned, because she really has a need not being fulfilled. Certainly would require a "sit down" discussion as to why she wants to see other men for sex.
Some guys, after a lengthy relationship, simply get lax and even lazy in taking care of their spouse's needs. If that's the reason she's wanting to see other guys, its probably a fixable situation.