I’m very sorry that you find yourself in such a difficult spot at middle age. You are not at all alone. Many people in midlife these days find that the job market is changing too fast for them to keep up. Trouble at work can spill into every aspect of our lives.
I don’t think resurrecting the guy in the mirror will be helpful. He can only give you the advice you have within you. If you had what you needed in your own brain, you would have solved your problems by now.
You and your wife have somehow lost the ability to work together as a team to solve your current situation. In your discouragement, you are each withdrawing into your own corner and feeling more and more alone. That isn’t helping either of you.
That suggests that the best thing to do is to find outside help. I strongly urge you to find a couples therapist to help you sort out the trust issues and to put your marriage back on solid footing.
An 18 year marriage is absolutely worth trying to save. I strongly believe that people who once loved each other can find that love again — but not without some work. Couples therapy can help the two of you forgive yourselves and each other and re-examine the terms of your relationship so that you can get back on the same team.
I wish you well.