I’ve been told basically to figure out what works for best me when I’m in crisis and use whatever it is to get through it.
This sounds weird to me. Almost like permission to have your own affair or some similar sorta garbage.
So, the way I look at it, you got two or three different things to address here, and finding a book isn't really gonna be as helpful as you might want it to be... mostly because of how personal this shit is.
First thing first - taking care of yourself. You are a living example to your kids for how to properly deal with it when shit hits the fan. It's five years past dday, but it doesn't make it any less important... and depression can be one of those recurring bastards that hit yearly like taxes.
Depression is all to common for these things, and finding ways to keep yourself afloat is important. Exercise, medication, journaling, meditation, etc... you know yourself best for what is going to help address that piece of the shitfest.
You are strong and you've been through the worst part of the pain already, yeah?
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Secondly, you've got to protect yourself. While you have posted in the reconciliation, which shows you believe yourself or want yourself to be reconciling... I personally can't help but notice two important details you mentioned. That your oldest is close to graduating and that she is reluctant and hesitant.
These two things lead me to suspect that she might be dragging the marriage out until the oldest graduates and plans to initiate a divorce once that happens.
My advice in response is to watch out for clues of this, and safeguard yourself if you find them. I doubt you want to be blindsided by yet another surprise if she is planning on on divorce.
This includes finding hobbies or stuff that you enjoy doing and would continue to enjoy if you two separate. Fav foods? TV shows? Etc. Etc.
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Lastly, it sounds an awful lot like you're unwilling to entirely commit to reconciliation because she hasn't shown she's willing to put in the effort... which is more than fair on your part.
I don't know what either you are her are looking for with regards to signs that your relationship is on the mend, but if you haven't even considered what those signs would be, then I'd suggest putting some thought into it.
Course, the reverse of the optimist is the pessimist and you could also put in thought to what the signs are that the marriage is doomed to fail... if you do this, though, then don't forget to also consider what you will do when you find those signs.
Wishing you strength!