Your knowledge about how cloudflare is astounding. How do you think cloudflare inspects the traffic ? Think about it for a moment, then realize that all the data entering into your site comes encrypted BUT only until it gets to cloudflare, then it goes to plaintext so cloudflare inspects it, then gets encrypted again with the certificate you provided. Think about it a little more and then you will see that all the data leaving your site will also get to plaintext while inside cloudflare datacenter. Therefore by using cloudflare you made SSL pointless.
You need to give up now... you have absolutely no concept of how things work, please stop trying to guess.
The Key/Cert pair is installed on Primary server.. the data passing through Cloudflare is enrypted.
Cloudflare is basically just a proxy with some major bells and whistles added.
Goto bed and let the adults talk.. your input is both wrong and irrelevant.