Very good, Manuel Moe. I am exhausted so I hope you mind if I am brief
At our age we either have to accept things as they are, or start over. We have to decide if something is worth starting again for. If we aren't willing to start over, we have to have the courage to accept our lives largely as they are.
If you love your wife, if you are a good team, if you have children, these are things to weigh.
I remember I was a juror in 2001. The defense attorney illustrated reasonable doubt with several dozen paperclips: he explained that even if there were a dozen paperclips on one side, if there was even one paperclip on the side of reasonable doubt, we should vote not guilty.
Perhaps that is analogous to your situation: is one paperclip of, frankly, a deep disconnect (ie the existence of depression) of a reasonable doubt.
Only you can decide this.
Either have the courage to start over in your romantic/intimate life, or have the courage to face your life as fate/God/your choices have created.
For all his manifold faults, Mr. Depression, like his equally reprehensible cousin Mr. Poverty, is completely egalitarian: while it gives me no pleasure to say this, your wife should bite her tongue, as Mr. Depression is liable to strike anyone at any time. He can even strike people who don't believe in him. While I don't want your wife to experience depression (far from it!), each of us living people are candidates to fall into Mr. Depression's icy hands. This may give her some empathy and compassion for your struggle.
If you ask me, I'd say to stay with your wife, especially if you have been together for some time. Just that is no more, and no less, than one opinion.
What I am certain of is that you will need to face this with courage.
Courage is the only answer.
Work is love made visible. -Kahlil Gibran
A person with a "why" can endure any "how". -Viktor Frankl
Which is better: to be born good or to overcome your evil nature through great effort? -Skyrim