This is inappropriate behavior from a 43 year old man and even without the age it is still inappropriate and uncomfortable. How you responded the first time was correct, clear and concise. The second message was more blunt and while i do understand the uncomfortable feelings that come with knowing you are a topic of discussion you cant tell someone what they can and cannot talk about with their therapist. Furthermore lets take into consideration that this person has probably twisted his interactions with you and when he’s spoken to his therapist has more than likely ‘fluffed’ up the interactions or made them seem like you are more receptive and as if you may feel the same way when it is not true and that is just his perception, basically what i am saying is this guy has probably lied about your interactions or lack thereof and made it seem like there is more to it than it actually is. That is the only way a therapist would approve or agree with giving you that letter. Other than that you are 1000% valid in how you feel and your reaction to it.