I need an opinion

 I really really really like my best friend and I told him how I felt and he told me he felt the same way but he wasn't ready for a relationship... so I was okay with that and we start getting closer and closer and suddenly he's constantly talking about sex. I told him I wasn't ready for that with him and he said he respects it but every so often he's pushing the subject... I really don't know what to do and he knows I want more than a friendship...