Spend a bit of time apart...a weekend, a week or two if you can manage it.

Absence makes the heart grow fonder... or, out of sight, out of mind?

You decide...but in my experience having some space and time to one's self (which many people in committed relationships do not get enough of) helps make the partner seem that much more special for not being available at every moment...

Also a medical check-up, some fresh air and exercise and some damiana tea wouldn't hurt...