All of what you've said makes sense. It's going to be hard convince her that I'm happy when I know those first few months are going to be tense--their third doesn't like me much, feels threatened, etc. And it's a big adjustment for me. Don't get me wrong, I am excited, and I'm in love. The thought of not seeing these two again is downright painful. But man, I am not looking forward to these next six months of conversations with my mom. We've been close my whole life, it's really hard to see her so sad.
What about her arguments that they could try to use DD against me down the line (if they were crazy, which they're not, but Mom is pretty convinced they must be). The other big fear, which is actually a bit more realistic, is that DD's dad's family will find out from facebook or something, and try to take DD away. We'll be living on the opposite side of their state. So she's worried about those worst-case scenarios, too. The second one, I can't make much headway on. I'm not super concerned about it because as far as I can tell, the relationship structure is legal in their state, they just can't call non-married spouses for what they are (bigamy laws). But it's generally a more progressive state, so hopefully the law would be on my side.
Aaaargh. *sigh* I want Mom to be happy for me. It won't happen soon, but geeze...this interim is going to be pretty intolerable.