Well, it needed to come out one way or another, and Im glad that your sister said it rather than you. But now you need to make sure that you dont mention it again. She knows how you feel and you keeping the pressure on will just push her away more.
I think that sometimes the WAS doesnt try to come back because they dont realize that someone is willing to forgive, and does want to try again. But its a heck of a fine line to communicate that message, and not be pursuing!
I guess I gave the wrong finger to the wrong man...