we have been together about 3 1/2 years. married since Feb. got 2 dc 5 and 2 and the older one is not DH's, he is from a prev marriage. we have a generally great relationship (have had a few bumps along the way but fine now) and we really are crazy about eachother, great sex life etc.
we had a great holiday together recently just the two of us (left dc with gps) we went to america and had an absolutely amazing time.
but since we have been back, about a week ago, he has been miserable and negative, keeps saying he misses being on holiday, well i do a bit too, but i am much happier being at home with my kids and everything i know! its like he is pissed off to have all his responsibilities back 
then last night we had a few drinks at home and he started saying he feels old (he is 40 soon) and he feels he looks old and fat (he looks neither, he is very attractive IMO.) and he hates that he has grey hair (he has it dyed) and saying that having a young family and younger wife (i am 31 and dc are 5 and 2) makes him feel even older.
and i basically said, FFS, get a grip, what do you expect from being nearly 40, no one can look 20 forever! and some people have got REAL problems, at least you have your health, family, a home and a job etc. and i told him how good i think he looks as well to try and re assure him but i'm not sure it worked :(
i have noticed as well that at weekends he often wants to "farm the kids out" (ie to gps etc or when DS goes to his dads) for want of a better description so we can do fun stuff and spend the time together, which is great, and we do have a good time. but then when we do have the kids at the weekend he seems to dislike doing "family" type stuff as he finds it "twee"
so we end up just doing boring stuff like food shopping etc, which he also hates anyway. :(
sorry for long post, not sure what i'm asking, just want him to be happy and for us to be a happy family.