NEED HELP IN BED!!!

Hey guys!!! I need help ASAP!! Lost my virginity two or three weeks ago to my SO of nine months. So far we've f*cked around twelve times. All were AMAZING! But I just can't seem to orgasm... I can feel a climax but not like any other climax, it feels different. Almost like its ticklish? Don't get me wrong, Ik it sounds really weird but that's the best way I can describe it! I've orgamsed before when he fingers me or if I pleasure myself, but never during sex! It's not painful most of the time either. He gets so sad when I don't and he does, he can keep going but after 45 minutes- hour he gets tired and I end up not in the mood, both parties suffer!!! Any ideas let me know!!!