Wist So far as I am aware there is no government statistics held in either the USA or Au on the divorce rate of FSU/USA-Au couples, however there has been a couple of credible studies conducted.
One that springs to mind was completed by a Phd student from Long Island and if I remember correctly (It is quite a while since I read her report) I think in the +5 year married group about 80% were intact. In the < 5 year group it was considerably higher. This compared to domestic failure rate in both USA and Au of approximately 50% (5 years+) makes the stats look quite good for the FSU/Western marriage.
Nevertheless, statistics, like studies can be slanted to achieve a predetermined outcome, so one needs to be careful of such studies.
I don't know about the USA, but here in Au, the number of Au/FSU marriages has been blown far out of reality in the media during times past. I recall seeing a program stating the 1000's of Russian women marrying Au guys, so under FOI, (Freedom Of Information) I approached the department of Immigration for actual numbers of Russian woman married to Au guys between the dates Jan 1 '04 and Jan 1 '06 and actually living in Au. The number came back to a grand total of 92 if memory serves me correctly.
I can't possibly have access to data on this, but a fair amount of research suggests to me that at least 3 of that group are now seperated or divorced. There would logically be more, but I am inclind to think not a great deal more. Maybe 10%.
FWIW
I/O