Which is more painful: To leave someone or to be the one left behind?

This is not about relationship break-ups. I'm talking about a married couple where one of them has to leave in order to work overseas. My husband and I are both qualified to work in Singapore and can do so within the next couple of months, we just have to decide which one of us will go. Of course we have to study our situation to also consider what's good for our kids and all other matters. I just want to have insights on people that already have experiences relating to this situation. ^_^