I'm not sure I've posted this yet...but DAMN. That's cold to set your S up for you going out on a date 4 or 5 days later with someone else. My W and I separated before she had s chance to do something like that to me. I just want to say, outside of the DBing thoughts, that those actions royally suck.
It's cold, it's rude, it's selfish, and it hurts us so much. And yet, we still Love them. And I don't fault you for still loving her.
Keep your chin up Dif. You can and will get through this.