This is indeed a big issue with international marriages. The solution I thought of (because I was living in Japan for few years, so may someday get stuck in a similar situation) would be to steal the kid before she does, like using holidays abroad, or even just like taking a fly with the kid after school or something. Basically boils down to firing first. Risky if the spouse find it, and of course that mean leaving a lot of things (possibly financial assets) behind.