First, please seek help for depression and suicidal thoughts. There’s always a way out, but sometimes we can’t see it ourselves.
Link to Suicide Prevention Hotline: https://suicidepreventionlifeline.org/
I think it’s important at this point to let your wife know what is going on, and to make a plan together to work out of the situation. The longer you keep the secret, the more damage it will do to both of you.
Try starting your job search at a career services center that can help you determine your career aptitude. Finding the right type of job for your individual set of strengths and weaknesses can help you over the hurdle of wanting to avoid the “wrong job” pain of your past.
Here’s more on finding the right work when you have ADHD:
Penny
ADDitude Community Moderator, Author & Mentor on Parenting ADHD, Mom to teen w/ ADHD, LDs, and autism