Well a little bit of a back slide last nite

I sent a text to my exW last nite asking if she wanted to watch a movie (now this will be the first time I have asked to spend time alone within 2 days, Friday nite we went out to movie/dinner)
She said maybe as her stomach was bothering her from eating too much dinner.

Well around 8:30pm she sent a text saying "Im not coming over tnite. Im pissed and upset and i don't feel like talking"

Now I am like what did I do...so I call her and she pushes me off to voice mail. I sent a text asking whats the matter.
She says my SIL is pregnant & that should explain everything.

Just a little background, my wife and her 2 brothers no longer talk. This happened as the D was in progress she wanted them to cut ties with me and they pretty much told her he is part of out family and we will not take sides. My exW was very hurt by this and has not seen her brothers in over a year. They don't even talk. Now I am very close to her one brother and she can't stand it because they get to see my D10 and she never gets to she her godson. It goes as far as if there are any family functions they will not go if she is present. It is ugly.

Back to the text.
So I ask her whys is she pissed? She replies "beacuse of everythg. talk 2 u tom.
I replied. You can talk to me anytime you want.
She replies " trust me not a good idea ur part of the problem"
Now I am getting pissed. I have done many wrong things, but I didn't cause there family to stop talking.
I had to relax for a few mins as I was just about to send a nasty text back. So I decided to validate her feelings by saying " I can understand why your upset. Im hurt that u would be mad at me w/o talking to me first"
She says "ur part of the reason i don't see my neice and nephew and i won't be seeing the new one either, thats on them 2 but i had enough for one day"

Now my SIL that is pregnant my exW never did like and has had many words over the years. So I know that her having a 2nd child is eating away at my ex because after our D we could get have any more.

So what do I do here?
I feel like all this progress has been for nothing as this can be the road block she may not be able to overcome. She blames me for all of her family problems, how can she possibly want to be back with someone who she perceives has caused this much agony?