Unfortunately, there’s not really a way to go back now that the cats out of the bag. The friendship conversation doesn’t just make emotional feelings disappear. You’ll probably always wonder if he’s reading more into a conversation or if doing certain activities together remind him of things a couple would do.
So as far as what to do, I do think a little bit of distance might help him get over you for the time being. You can see how things are going over the next few months but I wouldn’t be surprised if there are some outbursts of “i don’t even like you like that anymore” or “i’m so over you stop thinking that”. If that’s the case then he’s probably not over you.
Overall, i think it was best that he told you how he truly felt. He no longer has to wonder what could be and will hopefully stop idealizing this imaginary relationship with you. Years ago, I had been on his side of things and getting that definite answer that it would never be nothing more than a friendship really snapped me out of it. I stopped putting effort into the friendship and that’s when I realized how little he had been giving me.
No matter what you try to do or how you handle this friendship, he probably will not get over you until he sets his eyes on someone else. So if there’s any way for you to help out in that area, I say go for it.