Dear :

Thank you for the interview at your office on [date]. I enjoyed talking with you and learning the details about the job of at your company.

According to your explanation, the person chosen will be required to work for at least [months/years] in [country/area]. After considering the matter for a couple of days, I have decided to withdraw my application for the job. Because, although I don't mind travelling abroad, I don't want to stay away from my family for such a long time.

Again, I appreciated the opportunity to meet with you and I wish you and your company all the best.

Sincerely yours,

[name]

[title]