Don't put him off, say that would be great! Do some cooking together now. If he doesn't know any recipes, show him your favourites. Google recipes if you want something particular but don't know how to cook it. Even if he only cooks meals on the weekends, it will give you a break, and you might discover that he is good at it and enjoys it.
we have tried but he really is awful...and gets really frustrated and misses ingredents...plu he said the trade off is i have to do the dishes after ....yuk i hate dishes id rather cook! but i bought a cafe style sanwich maker (one that doesnt seal the sides) and have taught him how to use this so he can make some lovely sangas now which is a great help