You're allowed these feelings, and to vent them ... glad you're doing it here. Don't wallow, though. Feel what you feel, then put up the STOP sign in your mind, and think or do something else totally unrelated to your M. Even if it's a computer game, or movie, or anything to take your mind somewhere else.
It seems as if all is well in her world, but don't be fooled. I'm betting she's saying all these things on FB to keep the fantasy going. No mother would leave her children without some feelings of guilt, let alone her H and M. Just continue working at GAL, and detaching. You will have new dreams. All you have to do is be grateful for that which you have now, and live in the present. For example, you have your precious sons, you are healthy, etc.
Take care.
Me:57 H:52 M:28 Got another lawyer last year and filed. D35,S/D twins28,D22 EA4/04 End? Who knows? "Life is like a mirror. Smile at it and it smiles back at you." — Peace Pilgrim