Short answer: a letter during separation should reduce pressure, not create a hidden deadline. Its job is to communicate honestly while respecting that both people may need space.
Say what is true now
Focus on the present: what you understand differently, what you regret, and what you are prepared to change. Avoid treating a written message as a contract for reconciliation or as evidence the other person must answer.
Use grounded language
“I have been reflecting on my role in this” is stronger than “we were meant to be.” The former gives the reader something concrete to consider; the latter can sound like pressure when trust is fragile.
Keep the request small
If you want to ask for a conversation, make it optional and practical. One invitation is enough. If no reply comes, do not use the letter as a reason to keep escalating contact.
Read the separation letter sample for a calm, accountable tone.