Cancer boyfriend...attentive at times, other times NOTHING ! what gives ??

I have a boyfriend, that is the zodiac for Cancer. for the most part he is attentive, warm, affectionate, then all of a sudden, he will just not call, not come over, and just disappear ! this usaully last for 2 days. so is he doing this for attention, full well knowing it is driving me crazy ? I sometimes feel he does this on purpose, because he wants to see how much I miss him, I dont know ? what gives ??