You may have needed to physically detach for your sanity and in order to emotionally detach. However, it does sound like going dark did make it easier for her to move on and leave. She didn't have to question what she was leaving behind because the door felt closed.
BTW, I think the reason OM called that one time when she was having dinner with you is because he probably felt a little jealous and threatened. If this had turned out to be a positive experience she might have left questioning her decision a little more.
Of course, that doesn't mean it would have stopped the D, or changed their relationship, but it might have made made the D just a little more difficult for her (and as far as I'm concerned, anything to make the OP jealous, or possibly react in an ugly way, is a nice little payback).
There is no arriving, ever. It is all a continual becoming.
