There have been a couple of situations over the past couple of days that, in retrospect, seem to have tested my healing and growth.
Wasband notified me a week ago that he was getting to the point where he is ready to introduce his girlfriend to the kids. Note - this is NOT an OW.
I talked about this with DD. Hearing her concerns about losing her dad, about the GF not liking her, about the GF's teen kids not liking her, dad moving away someday... I think you all know the anxieties a kid normally faces in these situations. I told her she gets to decide if/when she meets the GF. No one will hold it against her if she isn't ready or doesn't want to meet GF. We talked through her anxieties over the course of a couple days. And I let her stew on it for as long as she needed.
DD spun on it and landed very firmly on wanting to meet GF. Ok then. Wasband picked DD up last night and they met GF for dinner. After dinner, DD came back home. She didn't talk much about dinner at all (except to say that she now knows that she is NOT a fan of buffalo chicken wraps). I didn't push for any information, but reassured her that we could talk about it whenever she wanted.
Off to bed at normal time. About midnight, she woke me up and handed me a note that read, "I don't want things to change." Her eyes were shining with tears. She said she felt guilty because the GF seemed very nice and interested in DD, but DD just wants things to stay as they are. After an hour or so of tears and worries and reassurances and a gratuitous grilled cheese sandwich or two and a couple of silly laughs, she finally fell asleep on the couch. Today she's open and happy. Talking easily about GF and the dinner. Excited about going for a trail ride some day with wasband and GF. All good in DD land. I expect her to continue to cycle on it. Par for the course with DD and her processing.
Through all of this, I kind of expected to get angry at wasband, but I never got there - not even close. For me, it was like any other change in DD's life - new semester class schedule, starting summer break, going to camp, etc.
I'm pretty pleased with the fact that this entire situation was, to me, exclusively about DD. Not wasband. Not him moving on. Nothing residual. Hmm... tastes like indifference. Yay me. 
The other situation was this afternoon. DD and I attended a pancake breakfast for DS' firehouse this morning. DS was very proud to show us around and introduce us to the crew, and we got an amazing breakfast that should carry me through until dinner.
After breakfast, DD and I stopped by the drug store to pick up a few things, and ran into my XILs in the parking lot. We haven't seen each other or spoken in over 7 months. We had a lovely conversation, as you do when you run into an old neighbor or coworker, with DD asking them if they had met GF yet. They said they had, and DD talked with MIL about how nice GF seemed, and then we parted ways.
When I saw them all those months ago, I walked away both saddened about the loss of family connection and angry with wasband for causing that loss. But today? Today I walked away with a smile. They are people from a past life that I haven't seen for a while. The sting of grief is gone. I even enjoyed hearing DD talk to them about GF, as it indicated to me her lessening anxieties and growing comfort with the situation.
I feel really good about how I processed these things. Very pleased with the growth I've accomplished. Very pleased with what I see as healthy and positive reactions to what would have been painful interactions for me a year ago.
Progress! And pancakes! What more could you ask for? 
