It's perfectly normal to have a high desire and a lower desire partner. Problems may arise in a couple when they don't work with these differences in a respectful manner. Just like other parts of your relationship, there are times when you do things even if you're not really wanting to. Learn to like having sex because it's something that your partner wants and you can fulfill this desire for them even if you're not in the mood initially (and chances are that with sex you'll be in the mood very shortly after starting). It's possible to enjoy sex every time! Sure, it might not be mind-blowing every time, but you can still enjoy it.
Aside from general differences, there are common factors that research has found to be correlated with a decreased libido. A slide show from MedicineNet shows some common sex drive killers.
You can anonymously leave comments with other possible contributors to your sex drive if it's not included in the poll.