Why did the sex stop

I don't get It. We have been dating 10 months now and all of a sudden the sexual drive for him just stopped but mine has gotten stronger. I don't understand. I guess I should mention he is 25 and I am 22. Is there a reason for this or did he stop because he is no longer intrested in me or not like me as much as he used to?? Do I not turn him on anymore?? I am so confused! I keep up with my body and workout daily so I know the physical attar action shouldn't be an issue. Idk please help me... Anyone!!!