I know I need to break up with my boyfriend but I honestly do not know how

I (18F) have been with my boyfriend (18M) for almost 2 years now. We were friends for about six months before then, so we've known eachother for almost 3 years at this point. We met in very formative years in our lives, so of course I'm very attached to him and love him very much. However, I've reached a bit of a dilemma. I moved across the country for university and I just know things aren't working out. At first it was great: daily calls, checking up on eachother, communication felt natural. It honesly felt no different than being in the same city. Now, I feel like our communication has plateaued. We don't talk the way we used to anymore. Another reason we need to breakup is for a concern I made in a previous post that i don't know if I can post here. Refer to my profile if you're curious. And yes, I have communicated my concerns with him, which is why I know we need to break up. I know we have to, I just don't know HOW. None of my friends get it because they have never been in relationships before. When I expressed my concerns they didn't understand why I couldn't just ghost him. But I feel like I care too much to do that. I have no friends to talk to about this, my parents won't get it (I come from an African household so it's a bit hard), and I even tried talking to a therapist but she told me to stay with him and live life. But I know I can't because it's honestly getting to me. I feel like I'm more stressed than not being in this relationship. Does anyone have advice? Or has anyone been in a similar situation to know how to go about this. Real, constructive advice would be great please and thanks. :/