It is great that you are acknowledging your role in the breakdown of your marriage...you are clearly taking positive steps. However, I want to encourage you to remain astute and not to be too quick to take EVERYTHING your husband says as 100% truth. Here is why:
Six months ago, I had the bomb dropped on me. I recognized some truth to it...but some of it was just inexplicable. Foremost, he had never expressed unhappiness to me...and I am a sensitive sort that easily picks up on other people's emotions and am a good listener, so it wouldn't have been difficult to approach me. Like you, I have had a tendency toward depression/anxiety in the past, but I had been the happiest and calmest of my entire life for at least the last five years...so that didn't really explain WHY NOW he was suddenly unhappy or felt 'burdened'.
Less than a month after the first bomb drop (saying he wanted to separate), I found out about the OW. He claimed he had not met her until after telling me 'it was over' and I believed him...never mind that he had still been sleeping in my bed, dragging his feet on where he would live, etc., etc. while romancing her, but I suspect it was worse. Gradually - in part because of some things that I've learned on this forum, in part because of how 'advanced' their relationship was by the time I learned about it, in part because of odd things that he said leading up to bomb drop #1, and in part because of the hunches of my family - I think that he may have been pursuing some kind of relationship (not necessarily a physical one) in the weeks leading up to my first bomb drop. I'll never know for sure, but it seems more likely than not.
Now let me tell you, this is the LAST man I would ever suspect of cheating...and I still don't know if he was...or if he was just thinking about it...or if perhaps he genuinely just wanted out.
But a wise poster on this board named 25YearsMLC told me that very, very few men leave a relationship unless they've got their mind on another. I think that is unfortunately true.
The fact that your husband has refused to work on the M in counseling suggests to me that he is in a hurry to be somewhere else. He may not have pursued it yet, but its possible he's got someone in mind.
I know this is a painful thought, and I have NO evidence whatsoever to think that your husband is cheating. But I don't want you to say to yourself "THIS IS ALL MY FAULT" without also understanding that there is a possibility it is not ALL your fault.
I HOPE upon HOPE that your husband is not thinking about a relationship while he 'goes traveling,' because I think you are off to a great start in making the changes you need to make to save your M. So I want to talk about your separation...
I know you say that it is too hard to have your H in your house right now, but BELIEVE ME, that is exactly where you want him (even if he is cheating) if you are to have the best chance of saving your M.
Also, since you are separating, please sit down with him and request that he take three months without pursuing a new relationship. Tell him you are in pain, that you accept that he wants out, but ask him if out of respect for you - and in the chance that you might someday reconcile - if he couldn't just wait three months.
TRUST ME, DO THIS.
You may find out something you don't want to know based on his reaction to your request, but if there is no OW...or potential OW...then your H should be able to understand why you are making the request.
If he's been miserable for 9 years, then what is three more months? Right??
Me: 35 Him: 43 Together: 19 1/2 years 1st Bomb (IDLYAM): March 2011 2nd Bomb (OW): April 2011 He abandons home/bills/everything: May 2011 He's bought a new house for OW: September 2011