What do you do when the chemistry between you and hubby stops?

I've been with my hubby for 9 years and married for 3. We have two beautiful children and he's a wonderful loving father. We've not had sex for over a year (both our young children are bad sleepers!) I just don't find him sexually attractive, I still have a sex drive but I just don't feel that desire towards him anymore? I don't know what's changed, maybe me? What can I do?