Communication advice.

Hello,  
I very rarely, if ever reach orgasm with anything other that direct clitoral simulation. My boyfriend knows this but I'm not sure how well. Sometimes he is very attentive and makes sure he makes me come. Other times it seems like he doesn't care or thinks I don't care if I orgasm or not. And I do care!! The last month it's really been bothering me. I always make sure I'm pleasing him and give him random blow jobs all the time, not expecting reciprication. He never does that for me though. Our sex is amazing and I love it. We try new things all the time. But lately I have been resenting him for my lack of orgasms and it's driving me crazy! I know the only way to solve this is communication, my question is HOW do I talk to him ??? Thanks