Yeah i've actually got a similar question too.
Has anyone been in a relationship, then subsequently went on exchange and are able to comment on how that went 
I went on exchange for 6mo after my boyfriend and I had been together for 3 years.
We are still together now for 6.5 years and live together. Now he wants to go o/s himself for 6 months while I stay here to study.
I would say it went pretty ok the first time, would be fine with it again...but it's probably different for every couple.
We are people that see each other at home for 2 hours or so a night and then are working all day. We sometimes go out on the weekend, but we don't eat meals together, drive to work/school together etc, so we are used to being apart and daily bouts of separation work for us. Other couples I know need to be all over each other and talking to one another all the time. It depends on the dynamic of your relationship.