A little over a year ago, I thought my libido was fine. A visit to the doctor showed that my Testosterone levels were "OK".
On his advice that I start some sort of cardio routine, I ended up going into a full blown fitness craze - running, eating clean, lifting weights. I lost 35 pounds and cut cigarettes back to a pack a week.
I didn't know it at first, but soon learned that weight lifting was significantly increasing my testosterone levels - and my libido went through the roof. Lucky for me my wife began to get past perimenopause and her libido is returning as well.
Looking back, with my wife's lack of interest and my mediocre state of fitness, my libido wasn't as great as I thought.
Barring any medical or genetic issues, if you want to increase your libido - get active. Exercise, eat clean, and if needed, lose some weight. If your partner's libido is lagging and they are not willing or are unable to improve, you alone have to decide to whether you will let it drag you down with them or not.
Of course stress and general state of mind can have a huge impact as well.