21F Almost-break up crushed my confidence…how do i speak to him 23M

So I’ve always had poor social and conversational skills, even with friends and parents, I was always a “seen and not heard” child. I’ve only started dating the past 2 years and I never saw myself doing so as I struggle talking so much. My problem is that no matter how much I’d like to start/maintain conversation, my brain cant even come up with anything to say.

However, ive been with my current bf for 8 months and i think its been going really well. He understands that im quiet so can respect comfortable silence when it crops up. He constantly tells me that im loosening up and getting better at talking, until one day out of nowhere, it becomes too much for him.

We almost break up bc he feels we aren’t right for each other because i barely talk and im assuming that i dont stimulate his brain enough. (he didn’t say that but he said that he finds it hard to spend more than a day at a time around me without getting bored). however, we decided to remain together, as he is going to have the same patience for me that i had with him whilst helping him with other stuff. he admitted that it was unfair of him to do that, especially since ive been so patient with him.

although i have another chance to work on myself, my confidence has been completely shattered. i feel like no matter what that im going to be closely monitored and that im not gonna be good enough. we have our first date tomorrow since the incident and i have absolutely no faith in my conversation whatsoever. its being made even more awkward now because of the situation. how can i rebuild my confidence and improve my conversation?