[JustPeachy]

And of course there is the less than noble motive in that I want my bdad to be angry with my bsister for having ruined this reunion ( because for all intensive purposes, she has made it very difficult) I don't want her to get away with it.

This could totally backfire. I would try to let go of the need to get back at your bsister.

How many years should I take her abuse? What, am I just supposed to idly wait and bide my time and take all of her crap until SHE decides she wants a relationship? What about MY needs?

You shouldn't take her abuse at all and you definitely shouldn't take her crap. Have you tried confronting her directly when she is nasty to you? Or are you waiting for your bdad to step in and handle it? I don't think you ever HAVE to have a relationship with her, even if and when she decides she wants one. By that time, it may be too little/too late. And your needs are certainly important, just as important as anyone elses.

I can see how frustrating this is. You gave more info in your last post about how your dad is so passive and enabling with you bsister, and I, too, would find it infuriating, especially if I was the one getting the brunt of her nonsense. And just because you are related by blood does not mean you have to get along. Of course, you would like for it to be so, but it's not happening and you have had quite enough. Your bdad needs to stop making excuses for your bsister. You cannot control how he handles her though. It is apparent he doesn't know how to, and that's his issue. However, I do think he will have to try to understand your side of this if he expects to stay in a relationship with you, and understand that you are being ABUSED and will not tolerate it anymore. If he cannot accept that, I really don't know how you can be around him if bsibling is also around at the same time.

He apologizes all the time, as if it's his fault. He says things like " I've broken up this family. If you and Ellen were living together this never would have happened. I've created a broken family"

I hope this isn't harsh, but I think this is lame. He should work these feelings out in counseling, not with you. By throwing this at you, he is deflecting from the real issue: the fact that your sister is, in the HERE AND NOW, acting in a highly inappropriate and abusive manner, and he is doing nothing to correct it. What happened in the past happened and nothing can change that. And I don't think you and Ellen growing up in the same household would necessarily have solved anything. What's to say both of you wouldn't have ended up the same way? Obviously, your bdad is being very passive about your sister. Instead of taking an active stance in stopping this nonsense, he's wallowing in the past. Apparently, he is too afraid to confront her, and/or he doesn't know quite how to fix the situation. But again, this is really all his issue to deal with. I would explain to him that you cannot and will not tolerate abuse and you cannot be in contact with your sister under those circumstances, but would like to maintain a relationship with him, as well as other relatives you like. I'm just concerned that if they kow-tow to your bsister so much, and you set this boundary, they will see YOU as the bad guy. I hope this will not be the case, but sometimes things play out like this when you change family dynamics by setting firm boundaries and maintaining them.