I'm not aware of any legal reason why not. In this scenario, it would be important to obtain at least one other quotation for the work. The councillors would need to be able to demonstrate that, in appointing your husband, they have secured value for money. You would also need to be able to demonstrate that you had not prepared the specification for the contract, so involve the assistant clerk and at least two members of the council. Distance yourself as much as possible from every aspect of the process, including the agenda item under which the tenders are to be considered. Finally, be completely open and transparent about the process.