I can't imagine the whole family staying in one hotel room for two whole weeks! When our kids were younger we found it worked for a day or two at a time, but any longer than that we would need somewhere with separate sleeping quarters for the kids.
It's not just about, or even mostly about, sex, although I do think that's part of what makes a good holiday. With more time to relax, away from the stresses of everyday life, we tend to have more sex than at home and that's part of the enjoyment of a holiday, even one with the children.
But not having anywhere to relax in the evening after the kids have gone to bed, always having to tiptoe around, limited space for everyone's things, no washer and dryer, etc. That just wouldn't be enjoyable for more than two or three days.
This would be something where I would compromise elsewhere to be able to afford the extra space. Maybe even making it a 10 day holiday rather than 2 weeks.
So I don't think your husband is being unreasonable. Maybe he shouldn't have phrased it as being all about the sex - although you should be glad that he finds that to be an important factor, but I bet it would be a much more enjoyable holiday with separate bedrooms.