If you are a PR yourself and you are hired in Canada by a Canadian employer and posted to a full time overseas position, you and your husband would both keep your PR based on that. You would however not gain the right to apply for citizenship.
If you are a member of the Canadian armed forces or you work for the federal government or a provincial government and are posted to a full time overseas position, your husband may gain the right to apply for citizenship.
I do not know if embassy staff hired overseas as considered to be working for the Canadian government.