Stop trying to fix him and stop trying to save him from himself. That’s not your responsibility, nor is it appropriate for your role in the relationship. You are not his therapist. You are not his mother. He did not ask you to do this work for him. You cannot make the choice for him to get healthy.
You do need to “prove” to him that you are a safe person. You do not need to “earn” his respectful, open, and honest treatment for yourself. You do not need to wait for him to figure out if he wants to be with you on the terms which you are demanding. In this respect, you are the one who is being manipulative and controlling in essentially trying to force change onto another person in order to mold him into the kind of boyfriend you want him to be.
You know your worth? Wonderful. Now, figure out how boundaries work.
read this and maybe give therapy another go. Seriously, you still have some major work left to do.
You literally answered your own question with the first sentence of the post:
> My narcissistic mother literally views boundaries as a form of disobedience…
That’s why. Because narcissistic people do not view their children as independent human beings with minds, lives, wants, needs, thoughts, etc. if their own, but rather as extensions of themselves.
Narcissistic Personality Disorder Toolbox: 55 Practical Treatment Techniques for Clients, Their Partners & Their Children https://www.amazon.com/dp/1683731522/ref=cm_sw_r_cp_api_glt_fabc_02MB8606140JY9ZBK4GD idk for some reason the link didn't work lol. This book.
Yeah your situation is quite complex honestly. Don't have kids so can't relate to that part but it's definitely something to consider as well. I'm glad you're looking for resources.
Highly suggest Dr Daniel Fox's work, specifically this book and his YouTube channel. Keep asking questions too. You're not alone and plenty of us with this disorder are eager to help explain things and provide resources.