I think going dim helps with W too - it can trigger curiosity, make a point that you can live without them, and "absence makes the heart grow fonder". I believe the separation time can help them reflect on positive things as well. I think the hard part is being patient - they will need to go through a period of time where they are relieved to be alone. This, for me, is the hardest part. Also, I have had at least three counselors tell me that W will have to go through a relationship, maybe two, before she will have any concept of what we had.
So, lucky me, just sit back and wait!
My thought to you - don't even TALK about OM with D3. If my kids bring OM up, I just nicely switch the subject. What's the point in knowing anything? If it negative, I would just torture myself with it. Unless kids are reporting something bad, I just change subject, and make it into something fun.
I've made it abundantly clear to W that divorce is wrong, she is hurting kids, and having a relationship is an affair. Even if it is just "friends" if there is a romantic tilt, then no way.
So, I've filed divorce, cut off contact, and when we do talk, I'm pleasant but very distant.