Perhaps everything that you described can be divided into two parts. On the one hand, 12 years of living together with a “clever wife, a successful director of a large company, a good mother”, three children, your huge contribution to this family. On the other hand, the absolute intolerance of the current situation: «I feel that I can no longer.»
It is very sad to read about how two close people, who could simply share duties and functions and perceive the family as a common cause, compete and quarrel. But what is the reason for your quarrels? Your feeling of unfulfillment? Thoughts that you are “losing” against the background of your wife?
It seems that you constantly compare yourself with your spouse, and, unfortunately, not in your favor. As if her career is not your common merit, you did not move to another city with her, you did not devote maximum time to family and children. It’s as if she exists, you exist, and you are not together … And the family is not your common business, where everyone invests what he does best.
It seems that both of you are fighting not with the outside world and external difficulties, but with each other, and in this struggle everyone loses. And of course, it is difficult to compete, quarrel with your wife, and then feel sexual desire for her. Either fight or sex … But you have something to fight for: a family, many years together, three children. It looks like it’s time for you to learn to cooperate in this new phase of life. Working with a family psychologist could be very helpful.