On the topic, I think it only works if both parties can put the past behind them. Mostly one or the other can’t. I think a lot of it comes down to the fact that the situation is difficult and confusing and one or both simply cannot deal with the complexity. One or both in a moment of anger over some trivial issue will at some stage use it as an excuse to hit out of the other, which is death to the relationship.The one couple I know where it worked, both knew not to think about the past, and concentrated on creating a future. Both good natured people. Gotta love them and their beautiful children.