Bismillahir Rahmaanir Raheem
Al Jawaab Billahit-Tawfeeq
It seems though there may be unsettled issues with your wife which makes you feel this way. Anyone who loves their wife dearly without any issues cannot be affected by Waswasah of this kind. If there are issues, it would be best to resolve the issues that might be causing this. Waswasah is from Shaytaan, therefore, general advice would be to increase in Istighfaar, Ta'awwuzh. Recite Suratun Naas with the intention of fighting these doubts.
No it would not count if there was no intention of divorce. Doubts that occur afterwards are from Shaytaan.
No this would not count. Signing a blank paper is opening yourself to fraud so this should not be done anyway. As for metaphors, if the metaphors are intended to mean divorce and it is signed then divorce takes place even if it is not said. However, sentences which are nothing to do with you and your marriage such as a business contract can have no effect on your marriage unless there was clear intention that you are divorcing your wife while signing anything. Please also read http://qa.muftisays.com?3463
And Allah knows best