Dearest [name],

As we’ve grown accustomed to exchanging messages online, I’ve reflected on how this relationship is progressing. Thankfully, it has progressed a lot better than what I expected it to. In fact, you’re one of the best people I have met online and that is saying lot since I have met only a handful. Unfortunately, I am not ready for what you want to happen next.

Judging from how we’ve interacted with each other, I know you are a wonderful person. Thus, I am telling you now this won’t work out between us. I am confident it will work with you and another person though. This doesn’t mean I am asking you to no longer message me though. I would be more than happy to stay friends with you.

Truly yours,