I guess I don't have much to say today other than what many other's have said.
Who knows what impact this had on XH or OW. I don't even think you really care at this point because you feel your XH is lost for now. I think you found this information out because you needed to hear it. There is nothing wrong with that at all. I think sometimes getting more of the truth - what really happened - helps us to deal with it rather than store those things away only to resurface later. Often denial or burying feelings come back to haunt you. I know first hand this happened to me.
Good luck! I'm interested in what is next for Liz too. Please keep us updated.