STOP IT...you are a caring guy, very thoughtful, a good dad to the girls and very resourceful.
Your W has the problems...not you. Yes, it is grueling to know that everything you do - seems to not affect her. She has a problem...we all know that you are a great guy, one I'm proud to say is a friend and one that offers great advice.
You cannot control her moods, she's in her own world. The SBT will hopefully offer you an insight on how to crack the tough "hard boiled egg" that she is. You are doing everything right, but with little response. I wish she would go see someone, but I know it's her pride.
Rest up my Canadian Mountie, you will get help real soon. Don't get down, now, you have come a long way - it's her.
Anytime you need to vent, do so here - but show her that it doesn't bother you.