How do I (19 F) deal with the guilt of ruining my 3 year relationship with (19 M)?

I have been with my boyfriend for more than three years now. I want to start this post off by saying that I have taken complete accountability and responsibility of everything I did, and in no way do I think anything I did was right - I just need genuine advice on how to deal with my bf and my feelings now. I cheated on my bf last year, multiple times. There was physical cheating and also emotional cheating. There are a lot of factors that go into why I did what I did but that’s not what this post is about. If any of you feel like my reasons for doing so are important to the story then let me know I’ll explain further.

Anyways, my bf found out about everything all on his own. I barely owned up to anything myself. He has always been very conscious about me cheating or talking to guys which is what made this a lot worse. Of course, he told me he wanted nothing to do with me and cut off all contact. However, he would randomly unblock me to either ask me a question about what I did or to let out his anger etc. I had accepted the fact that we were never going to be together and started working on myself. Now, here’s the part I need advice on:

It’s been a few months since he found out. The first month after he found out was horrible, it was basically him showing me how hurt he was in the most bizarre ways possible. A month later, we started meeting and we eventually got back together. The relationship was not the same though, it felt like I was constantly walking on eggshells whenever I spoke with him. Us getting back together felt like we were growing from the experience and gave me a chance to actually prove myself to him. However, about 2 months later he randomly decided he wanted nothing to do with me. I of course respected that.

We have been on and off since then, it’s confusing because we talk every single day as if nothing has happened but we aren’t together. He still brings up the cheating of course, and we still talk like we’re together but I know we aren’t and I also know he’s been interacting with other females as a way to get over me. I don’t know how to react when he brings up the cheating. We’ve spoken about this maybe about 100 times (not exaggeration) and I feel like he’s too traumatized to hear me out whatsoever. I don’t blame him, but if he says it’s impossible to trust me again then how can I be the one to comfort him? I genuinely love him and have never pictured a realistic future with anybody but him and he knows that. He tells me that we will never get back together but the only difference is that there isn’t a label to us now.

I will never invalidate his feelings or feel like they’re “too much” for me to handle, and I apologize if this was too long, I just haven’t had a chance to talk about this with anyone. There are many details I’ve left out for the sake of this post being too long, if anyone has any questions about anything feel free to ask.