Talking to ones SO is often tough. The stakes are so high. EsPECially when the topic is sex. But friends and family also can rank pretty high up there on the stakes list, along with career status and income. Your bf may have some insecurity issues that make him defensive whenever he's afraid you're signalling that you're losing interest. With me and my DH it's often been the other way around: I go defensively ballistic, he just retreats. Months later we're finally able to talk about whatever it was, and so far it's always been some simple misunderstanding. Persistent but patient and soothing talking is one way to get through and clear things up. Physical reassurance (doesn't have to be sex, snuggling and cuddling are equally reassuring) is another.

As for sex drive -- no, you're not alone in having down periods. In my own case, the libido doesn't awaken just by thinking of sex, or seeing the DH, or coming home from a trip. It's just not on automatic. And worrying about whether it will awaken is a sure killer. But a relaxing cuddle, just for its own sake, will often have the extra dividend of sparking a brighter flame.