Guys are very visual and auditory. A million years of instinct can't be erased in a few hundred [monogamy]. Men's instinct is to have sex with as many women as possible to have their seed go on. To pass on their DNA, it is what drives all animals [especially male]. I know this will sound crazy but we are still animals.
Your boyfriend loves you but the 'sex drive' is a real issue. It means that he does not want to be without you, but, needs release to keep his animal side in check.
Try teasing him to enflame his lust. Wear some new clothing and be sexy without trying to be sexy. Try not pushing him for sex for a few weeks. Then when you have sex and you both finish leave him alone. Don't try to snuggle unless he does. This will shape his mind into thinking that the challenge is still there and he needs to be on his best to hold onto you.
Don't f#$% with him too much. Just enough to keep him on his toes!