Sex but don't cum?

My boyfriend and I have sex alllll the time I stay the weekend with him and sometimes during the week. We have sex like 5 times a day but i don't cum:/ he gives me head but he stops right before I'm bout to cum. Or he will start fingering me then he will want to have sex instead.. I make sure he cums. He always does all the work to and I feel bad . How could i tell him to keep goin when I'm bout to cum? I'm scared to tell him