Is it sinful to delay breaking the fast for an hour after the Maghrib Adhan while waiting for the husband, only drinking water at the time of the Adhan?

There is no harm in you breaking your fast with water; rather, it is an adherence to the Sunnah and in accordance with the action of the Prophet (peace and blessings be upon him) if you do not find fresh dates or dried dates. And your waiting for your husband until he returns from his work is a good deed, as it brings him comfort and endears him to you. It is known that hastening to break the fast is a Sunnah, not an obligation.