I am a 16 year old girl in a relationship with a 17 year old male and after I fellate him and he finishes, he is basically done for the night. No sex, no more head, nothing! His explanation is "he just can't" and his dick is tired. I like to get off as much as he does(even more apparently) and his inablitiy to keep it up hurts me, like I'm doing something wrong. I've talked to my coupled friends and they say 5-6 times a day is average for them (they are around the same age as us). Is this the product of a low sperm count? What gives?