Ex boyfriend problem

So my ex bf and I dated for 2 years and then we broke up because we feel like we are not mature enough to make each other happy. He told me that he don't want more fight between us and he want us to be friend. But for me it is very hard because I still have a lot of feeling for him. But we still have sex sometime and it is great. It is bad that we have sex? It is called friend with benefit?