I agree. Rejection may be a little harsh? Maybe she truly doesn't care and will have her special day with S on a scheduled weekend. That was very considerate of you to change the party and include her with the invite.
It's easy to take any non-positive response as rejection. I do it all the time. Indifference isn't the warm & fuzzy we want, but it's not rejection. Perhaps it's an effort on her part to get along and not make waves?
I think our spouses are really afraid to consider a future back in family. So it's a lot easier for them to put up the 'I don't care' mask. It'll take a long time of modeling changes for them to peak out behind the mask. Keep at it!
