You really did hang in there long enough. And even though divorce should be the last option, I really think you and the kids are going to come out of this ok.
Didn't you say she gave up her USA citizenship to become a German citizen again?
Have you retained a lawyer?
I sure hope she is not going to try to battle you over custody. That could get real ugly. And it is a losing battle in the end for her. She is entitled to her share of the division of assets and retirement. Dont be surprised that she is able to get substantial spousal support as you have been married a good long time. I was able to negotiate a buy out of spousal support included in the division of assets of which I refinanced my house to pay the whole thing off.