You should look for a therapist who’ll encourage you both to be assertive, confident and to take responsibility for your actions rather than encouraging disclosure without any sense of how that will help you heal the relationship.
It is fine to speak to several therapists while you find one that suits you both best.
This guide on how to deal with arguments may help while this piece on showing and sharing affection may be useful in creating a more positive environment for you both.
Your letter is a useful place for you to unpack how you’re seeing and talking about things.
Together or individually you may want to use the following resources to reflect on your relationship and find more effective ways to communicate: Meg Barker’s book Rewriting the Rules (particularly Chapters 6-9) The Couple Connection has forums, resources and a helpline (free) you may want to use individually or together.
This may be particularly useful if you are unable to afford therapy or need some assistance in preparing to speak to a therapist about what happened.
Might your presenting of events as being unimportant be contributing to the ongoing arguments you are having?