It really is sad isn't it? I too am feeling the crunch and periods of resentment having to do the single mom role too. The girls see their Dad consistently every week, but Im still doing it all as far as the parenting role is.
I got the 5 Love Languages for Teenagers a few weeks ago. There was a part in the book that describes how parenting is different for the full timme custodial parent, or basically the parent that has them the majority of the time, or maybe the one that didn't leave. Our roles are so much different and difficult, because our children feel SAFE with us. They know we all always be here. So they feel more comfortable to express themselves, especailly anger and frustration.
I've noticed my girls really put on a different persona with their Dad, they even did when he was still at home. The meaning behind this is that the children don't want to rock the boat with the WAS because they fear it will push them away further since they left in the first place. At first I had a hard time understanding why the girls were do different with me vs him, but now I understand. He always has been an absentee parent to a degree given his job.
I see MLC is real. I feel that way because I know that Im going through a life transition myself, but not crisis. The feelings I've had during this time are very much the same that an MLCer would have, except I stop at REALITY and know running wouldn't solve anything and make my life so much worse. I have a friend at work that's having some issues with her spouse and it looks like it's got MLC written all over it too.
Something interesting happened yesterday. Stbx dropped the girls off from their overnighter. He turned his truck off, walked them to the door, hugged them and left. He didn't look at me or say anything at all. I've sensed his mood shifted over a week or so ago, and he complained of having a migraine to me 2 days ago as well.
Past experience reminds me that migraines and mood swings with him equate to going in the rabbit hole for another 2-3 months. Then after than he'll come out and join life again. Whatever....... thank God for detatchment!