It's driving me mad but .....

My OH falls asleep the minute he sits down in the evening after we have eaten. Then he snores. We are both still working and he does work hard but why on earth does he not go to bed? I try to encourage him just to go up but he won't. Indeed I often go up alone and leave him snoring on the sofa. If I want to watch something on TV it is very distracting and often he insists we watch something else and yes ..... falls straight asleep in front of it. Actually the worse thing is that I like to share what we watch, laugh at the same things and discuss the programme etc. It's rather lonely. He is just the same at weekends. And when we have friends round or go out to supper it is becoming a local joke about him falling asleep at the table. He won't see a doctor and says I am fussing.