Strange how I could get dependant visas for my Filipina ex-wife's two children when both she and I had been out of the UK for more than a year and didn't even have an address there.
These decisions seem to get more and more 'questionable'.
Definitely appeal....and don't leave it too long.
Otherwise your partner needs to change his circumstances to meet the (stupid ?) requirements of the ECO, and then re-apply.
Your case also demonstrates how important it is to 'read the smallprint' on the visa application form, and make sure you are well covered for meeting any conditions which might be seen on your application as 'marginal' by the ECO.