Should I talk to my boyfriend about my past?

hey people.

i have a boyfriend, who really means a lot to me. i have never felt this way ever for anyone and he is so respectful and caring towards me, i would have never thought i would deserve someone like him.

now the thing is, i have been through some stuff in my past. my first relationship was abusive (emotionally, sexually, physically) and it sometimes is still on my mind and just a big part of me.I also still see my abuser around often and everytime i do, i panick and get triggered. I also have big self harm scars from that time because i was in such a bad place. (my boyfriend has not seen them yet.....)

The thing is, i want to tell him badly. because i have never trusted anyone that much before. because he is so respectful. for example, he asks me all the time if i feel comfortable when we kiss or do more and ask me all the time what is okay to me and what not.

I want to tell him but i am so badly scared of his reaction. what if he will think i am crazy or stupid or think that it is too much of a big deal that he does not want to be with me anymore???

He had some mental health issues himself in the past (abuse, depression, anxiety) so may he understands it better because he know how hard it can be. however , i am still so so deeply scared of loosing him due to opening up.

please please share your opinion on this, every answer is appreciated.