OMG - I burst out laughing when I read the question heading... that is so my husband...
If he is sick he HAS to nap, lets us know how awful he is feeling and how he can't do anthing. And if he has to do something it is like we are asking for him to carry the world on his shoulders....
If we are sick at the same time, I get do rest so I don't get better.
The way I deal with it is to ignore it... my daughter and I go out when we can and gernally try to leave him alone in the bedroom while we do our own thing. Maybe this will work for you? Don't make him a primary focus and maybe he will stop trying to be one...
Unfortnatly (and this is a big generalization) I think "we" teach our children that Mommy takes care of everything when they are sick. Little boys see the women taking care of them and grow up to expect that. Little girls see the same and grow up being the care givers. And the cycle repeats...
Not even sure how to address that, unless we can get more Dad's to stay home when their kids are sick...
(Again this is a generalization, I know a number of Dad's that are stay at home and do a great job).
Any way just my .02 cents!