Experience and level system

I 've noticed that my opponents gain more experience even when I significantly have more cs and kills than my enemy laner. My opponents lvls faster than i do. My duo noticed the same thing, he dominates the lane and yet he is still behind with exp and lvl. It is an important thing because i use lvl advantage to win trades. Did anyone else experience the same thing. I feel like experience system works in favor for loosing lane. Perhaps I m missing something and I don't notice that they do a jungle camp?