Hello,
1) Unless we go through the entire judgement and the record and proceedings it would be difficult to form an opinion as to why such a verdict came to be passed.
2) In fact the duration the marriage subsisted has no correlation to the quantum of punishment being awarded.
3) I presume all of you have been granted bail until the time you can move your appeal. If not you need to move the same court to get the sentence suspended and for grant of bail.
4) The only way getting out of this or trying to do so is by easy of moving an appeal before the High Court. Your advocate will help move the appeal with appeal the grounds and apply for the extension of bail during pendency of the appeal and suspension of the sentence until the appeal is decided.