This is a very interesting topic and the one that rarely gets discussed or explored in therapy or on therapy forums.

I also had a problem expressing myself freely face-to-face with all my therapists. Writing felt like a much better way of communicating what I needed to say. It allowed me to go much deeper right away and to relay all details and nuances that were important to me. I could focus better when I was writing, because when I would talk to a T face-to-face I needed to always make a connection with a T first in order to be able to bring up whatever I needed to talk about.

I've noticed that quite a few people have this issue in therapy, but, sadly, the profession doesn't recognize it as something that needs to be taken seriously. The only guidelines around it is to treat it as a "boundary" issue when it often has nothing to do with the boundaries.

To answer your question, no I had never paid for email contact in therapy, but, I think, that if the therapist is willing to meet your needs such payments can be arranged. The payments could be calculated based on the word count and on the number of interactions. I think, this is what therapists who only work online do. Those who provide online therapy sometimes have email as one of the options though video sessions seem to be more common.

So, yeah, I think, such payments could be arranged with no problem if the therapist agrees to working in this manner. This makes me think if online therapy might be a better option for some people all together.