Late to the game

[Free]

New here, so I'll start at the beginning.
Back in June, wife tells me she is not happy and does not know what she wants anymore. Then she asked for space. Like most others here, I never saw this coming. She mentioned things I have done that upset her, some of them from over 25 years ago. While I never cheated, drank, used drugs or abused, I was, at times, completely emotionally unavailable. I did the standard things early on, begging, pleading...etc. I validated her complaints, whether I agreed with them or not. I do not believe there is anyone else on her side, but I could be wrong. If there is, it's happening at the supermarket or library.
I read DB pretty early on. While it has helped me, it has done nothing towards R. We are both still home, but civil towards each other only. Nothing more.
We've talked about the future about 5 times in 5 months and it's gone from "I don't know" to "I think I want a divorce". The first time she mentioned divorce, I said that it's not what I wanted, but wouldn't hold her back.
Divorce hasn't been mentioned since, but I've basically shut down on her since then. I have GAL in spades and it is going great.
Early on, I went through the brutal daily wave of up/down emotions. It is still there, but with much less intensity.
We've tried a therapist together a few times, but it was useless unless both want to make an effort. She did not. It just turns into a husband bashing party. We are going to counseling separately though.
As it stands right now, I'd like to save my marriage. I do still love her (The old her, not the cold, unemotional her).
Not sure how much longer I can live this way and I'm not sure which direction to take. I'm afraid of giving up too soon and I'm afraid to keep hope alive only to be $hit on again.
I am basically on the LRT plan right now with no end in sight. The kids (S 21, S 17, D 14) know something is way off but have not said a word. I'm sure that they know exactly what is going on, but do not want to make it real by asking.
Other than LRT, I'm not sure what to do next.
Also, I've read just about everything on this site. Sandi is brilliant and spot on with her description of the WAW.
My question at the moment is how long do I let this go on? Is there anything I haven't tried?
Any advice would be appreciated.