You act like you are happy with how things turned out in your life.
You can talk to her and be friendly (think how you would talk to a neighbor). Avoid relationship talks and if she brings it up, just listen and validate. Even if she mentions she thinks it's time to get a divorce, act cool and unaffected by that.
Act just like you did before you met her and had no emotional attachment to her. A cool, confident guy, who has lots going on in his life.
This is what I was thinking. I just wasn't sure, because I've been going dark for a long time now. So it would be a matter of switching from "going dark" to "friendly neighbor". Thanks!