My experience tells me that husbands become the guy miserable conversations happen with. The bills, the household breakdowns that are still unfixed, the household breakdowns the kid caused today, the kid's grades/behavior/etc. Love may be present, but it has very little opportunity to get across.
Then there is "the guy". She doesn't nag him about that cracked windowpane that needs glazed. She doesn't ask him why they can't afford a better car. The only conversation they have is him telling her how wonderful she is, and her eating it up...plus of course her telling him what a jerk her husband is and him nodding compassionately.
If you can say "you're wonderful" and tune out all the whining about the husband for a couple hours a week you can borrow a wife easily for a couple romps a week. If you get good at it you can have a whole stable of wives to choose from and be romping to the limits of your physical capacity. The problem is they all want to ditch their husband to be with "the guy who really understands them", who if he is smart recognizes that if he were with them for more than a couple hours a week he would be more hated than the husband is.
Is there a solution, from the husband's point of view? Maybe. If you really think your wife is the greatest bestest only one for you...let her leave. She will find out very quickly that the guy who thinks she is wonderful in very small doses has no interest at all in a steady diet of her. Do not divorce her, or she will be living on your income and have no complaints about Mr Wonderful...let her really examine how interested he is in supporting her.
And don't be mean about it. When she is crying and complaining about Mr Wonderful, do what he did. Tune her out, nod compassionately...you can do it for a couple hours at a time. While she's gone, live well. You may find out that the realities of demographics will have a steady stream of women trying to pick up her discard. They can either keep you busy until she gives up on Mr Wonderful, or you may find that she wasn't the greatest and bestest after all.
A key point...you have to do this letting go early, without bitterness, and with clear evidence that it is all her idea, and without indication that it may be permanent. That way if it does become permanent she is on the short end of the legal stick as the mom who ran off and abandoned her family.