You can validate your WIFE, and her feelings, while not supporting her DECISION. Big difference.
"I'm really sorry you feel this way; this sounds like it's very upsetting to you. Please understand that I don't want to get a divorce -- I want to work on the marriage. I don't want us to go to our death beds, regretting that we didn't give it everything we have, and that's not what I want to teach the kids (if you have children)."