So we are in a group and I had noticed he leveled to 38 (I think). So I checked my exp and I still needed half to level to 38. So then I went around killing things alone and finally leveled. But then I ran into a big group and accidentally over shot him. So I was like 10,000 more than him. Then a few days and levels later, He leveled before me(40). Only by a few thousand. Then the next time we leveled to 41, he was around 8,000 more than me.
We are the same level, we both were Rings of Mara's, we only play these 2 characters with each other, He doesn't war any exp boosting stuff (I was for a little while), We do the same quests, kill the same enemies, and We both don't have ESO +.

I don't know if it matters but I am a Lvl 41 Orc Dragonknight Werewolf and he is a Lvl 41 Argonian Templar Vampire. He also has a Vet character but he doesn't think hes done any CP with EXP gain, or if it even exists.

This is all that I can think of so people ask if theres anything else. Thanks for the help!