I am as sure as I can be about the affair. He might be going through an MLC, but self-doubt and wanting to (probably) divorce me are the only real signs. No crazy expenditures, no partying. He's an engaged parent. He is still kind and thoughtful in his daily interactions.
Depression is a major part of MLC. He may be in a lower energy type of crisis.
As far as what to do, turn the focus onto yourself, making yourself into a person only a fool would leave.
You know sometimes men are attracted to what they can not have. Absence also make the heart grow fonder. You can not love him out of depression, he has to hit rock bottom and want out himself.
