I can't support with any statistics. Sorry, not a data
collection bureau.
I think he should go overseas because life is short and one should
make the most of every opportunity given. It's not just about the
money, or that he can work locally... it's about building up
experiences and the long term view of a career.
I think the relationship can survive, with some conditions:
Relationship must be very secure and stable before
seperation.
Both parties have a mature mindset. Means they're not prone to
minor bullsh|t stuff like "Girl A likes Guy B, Guy B likes Girl
C..." "He never send me goodnight SMS, very sad" etc
Both have a life of their own, outside of being a couple. They have
things like work, hobbies, to occupy their time. If now, a large
portion of their time is spent together, they are inseperable and
very dependent on each other for most things, then seperation will
be difficult.
There is a certain objective at the end of the 2 years seperation,
and couple is committed to it & the relationship. E.g. couple
is sure that they want to have a long term relationship. Or plans
to marry. Else they may ask "what's the point?" somewhere down the
line.
2 years isn't a long time at all. Keep in touch frequently. If
possible, arrange for her to go over, or him to come back for home
visit, a couple of times a year.