No more sex?? !!! please help!

My boyfriend and I been dating for four years already, and I notice that we have a lot of sex. So yesterday I told him that from now on I don't want to do it no more bc I don't want out relationship to be about sex. He was very upset and said that it's part of a relationship, that if there is no sex there is going to be a lot of stress. Is that true? Am I "over reacting" or am I doing right ughhh please help