Boyfriend's libido

My libido is higher than my partner's. it's always been that way. But we're young (20 and 21) and I feel like it's not normal for his to be so low when he's so young. I'm worried something is wrong and it can't be improved. it's severely affecting the way I see our relationship and it's messing me up. I've considered it might be testosterone but I know that that would also be affecting other things as well. But we didn't have sex for close to a month and then suddenly did it 4 times in the last week so I'm just so tired and confused. :(