My wife and I have had two separations that lasted over a year, and in each case we made formal financial arrangements. We have come back together, and I think we're doing pretty well (except for that pesky little thing called sex). If you want to keep your options open, call it a separation, and make it clear that you are open to a happy ending.
But separate financially. I've seen too many divorces where the man walks out leaving the woman with all of the debts and none of the assets because the guy was thinking strategically while the woman was thinking about the relationship. Do a good clean financial separation, get yourself in a position where you can function, and then think about the next step.
When we were separated, each time we needed some months to grieve and get some stability. We had light, friendly, careful contact during those months. The second time, we spent a week together in an intensive program called Recovery of Hope, which was offered by the Family Life Resource Center in Harrisonburg, VA. It was extremely helpful, and drastically changed the way we relate to each other.
A separation is just that. Most separations do end in divorce, though, so you have to be intentional if you do not want that to happen.
