My name is ***** ***** I have been a Veterinary technician fo someoner over 35 years and have an interest in wild Birds.
Sparrows are Monagamous and are usually mated for life.
The fact the male has not been around does not look promasine. Something may have happened when he was out looking for foods or on a flicght were he was injured and could not get back. He may have been trapped by someone, caught by a cat and injured or caught by a Bird of prey like a Hawk.
Unfortunately, those are perils these Prescious little birds face if they venture away from their nesting area.
If there is any way possible he will make it back to his mate.
I know you are concerned, but I have to be honest , every day awy from his mate and home tere is more of a chance he will not make it hom. It is the cycle of life with small birds as they become prey for other animals.
I do hope he makes it back becuse his presence seems to give you joy as well as his mate missing him. THere is a possibility if he does not come back she may take a new mate.
Please reply if you would like to discuss this information. I am here to assist you with any concerns you may have. My goal is to give you the best information possible and I do hopt to earm a positive rating.