I had agonized for months about this, given how she reacts to just about anything I ever say. And I had gone over every possible option as far as setting up the conversation for the least chance of her saying anything dismissive or judgmental. It took me this long to come up with the one sure-fire way to get her out of her negativity for at least a few seconds while I told her about the baby.
It was simple. It was easy. It was brilliant, if I do say so myself. I used that negativity to my advantage, setting her up against her least-favorite sister in a way that let her be the one who could "win" in the good-news contest. It was so obvious, I can't believe that I didn't think of it before. In any case, it worked, its done, she said most of the right things and now we can get on with it - she has staked a claim in the happiness of this situation, and I know her well enough that she will not deign to reverse that position now.
I just wish I had a mom that I could really share these things with. I'm so wistful about other people's wonderful relationships with their mothers. I don't need any more therapy to see that she is doing her best, that she can't help it and that she has so many other things that get in the way of being the ideal mom that I can't expect anything more that what she does try to give. But I'm still nostalgic for a mother-daughter relationship that I never even had, if that makes sense. I remember reading Little Women for the first time, and being sadder for the fact that I would never have a beloved mother like Marmee than for Beth dying. Completely selfish interpretation of a classic, but it's true.
Still, my mother came through today. Even if she needed a little manipulation to get there, she did seem to be genuinely happy for me. She asked if she could be the one to tell her mother, of course, which was fine with me - why not encourage the mother-daughter relationship where I can? Now that she knows, everything seems less fraught, somehow.