The fantasy in the mind of the spouse who has decided to move on to another is rarely met.
I recall my ex sending me an email in the first days after we were officially divorced, saying that she thought we could still do things with the boys together and that we would always get along because she never saw us as one of those angry divorced couples. (Or something along that line, it's been awhile now.)
Being friends works for them because it does two things. It allows them to pursue their new and illicit relationship, and it assuages their guilt if they can be friends with us at the same time.
Somehow they have managed to take a long term relationship that was promised to last forever, and end it by saying "let's just go see other people and be BFF's!!"
How utterly juvenile...
The best thing you can do for yourself right now is to continue to pull back with grace and dignity. To hold true to your principles about what is proper and what is not in ending a relationship. And to remain firm in what you will tolerate and allow yourself to be exposed to in the behavior of your still-spouse. Then do all these things without anger or vindictiveness, but almost matter of factly. As in, "that's just how I believe it needs to be."
You continue to honor the fact that you cannot control her by allowing her to proceed down the path she has chosen without throwing fits, breaking down in tears, and screaming accusations, but you also make it clear that you believe it is wrong and you are disappointed that she has made these choices.
Then you get out and begin to discover what Tim's new life is going to look like.
As you said, she must deal with the repercussions of her choices and actions. And trust me, she is not yet even fully aware of just what those repercussions are.
I told my ex one day, just prior to the divorce but after it was clear that there would be no reconciliation and that she was pursuing her soul mate....
"One day you will see or think of me and realize that you made a horrible mistake when you chose to leave."
No anger, no whining, no pleading, no desperation. Just calm, cool, and collected fact.
And I sincerely meant ever single word.
And that's part of how I knew I was ready to move on.
Stay strong Tim. I believe you are working this out just fine.
Blessings,
Bill
"Don't tell me the sky is the limit when there are footprints on the moon."