Meant "informally" just in the sense that it was not a formal legal Separation.
I'm no lawyer and I know things can vary by state, etc, but for reference in my sitch I had a somewhat related marital property issue I checked on when I had a free lawyer consult.
My car is actually in my wife's name because when we bought it she was able to get a slightly better interest rate. In my case, L said it didn't matter and it still counted as marital property legally, regardless of who's name was on it.
I totally understand the desire to not let things get nasty, and I'm in the same place right now, but for what it's worth I am very glad I ended up doing the consult. I got a number of questions answered and had a lot better grasp of what the potential ramifications of things could be, and even learned of a couple options I wasn't aware existed. Not knowing for sure was causing me a lot more angst than I had realized.
Me, WW - Upper 30s BD - Apr 1 2016 EA - Apr 7 2016 (discovered; ongoing for months; did not confront right away) Confronted wife about EA - May 17 Wife sent NC email to OM - July 11