I actually agree Melodylane, marriage is not something to be tossed aside. There was a good reason that this lady and her husband married in the first place and it should, at this stage, as it is just a thought, be imperative that action is taken.
I am not suggesting for a minute that she start with someone new. That is completely uncalled for at this stage.
I am merely pointing out that it seems and easy option and everyone who looks happy becomes attractive when life at home in your own marriage is terrible, but that is just a sign that things have to be done to avoid further complications. Another man and the fall out of a divorce should be only a very, very final resort.
Are there children involved here ?
Time to think is vital. But not alone. I know that the best thing I ever did was force myself to talk about how I felt with my wife and that, to someone who had not done that in his entire adult life, was not easy.
Suddenly finding that you conveniently forgot about all that one does have in common with a spouse is not only a revelation, but cathartic and wonderful. Start at the bottom and work upwards and hopefully what looks attractive on the outside becomes something that one can achieve on ones own.