In your 2nd paragraph, divorcing him from bed and board when he has moved out is a moot point. D from bed and board is simply a form of forced separation. You are still married till final D papers are served.
Are you still involved with this person? If so, that is a big problem. I don’t know about “proof” the marriage was in shambles. That is his side of it. The other side can portray the marriage they way they want to. They will say that there was love and compassion and that you destroyed that. whether that is true or not is irrelevant. Here is the thing about AofA. Most of the time it isn’t about you. It is about them fighting over assets. You are just “collateral damage”.
As to being served via certified mail… That is one way to do it. I don’t know why they would though. It only costs about $20 to have the sheriff serve you. If you refused to sign for the letter (which you had every right not to) they will simply serve you via the sheriff. Could be at your home, place of work or anywhere. The problem served you via mail because they don’t know where you work.
What did they file in Nov 07? AofA has a statue of limitations of 3 years I think. Hope this helps.