How to get courage to breakup?

I genuinely want to know how people do this, especially if it is a long term relationship. I (19f) have only ever had one boyfriend (19m) and we have been together for 6 years. That is nearly a third of our lives have been with each other. Dumpers, how do you do it? He has been a major part of my life for so long, and I still love him, but the negatives outweigh the positives. I hate to say it but his mental issues are a large part of it. When I say mental issues, I mean BPD, Depression, suicidal, Antisocial Personality Disorder (you may know it as sociopath), and others too. I do not judge him for having these issues, but I just can't take being a target for him lashing out anymore. There are many other things too, but I won't get into it here. How do I even go about it? Everyone knows us as being a couple, it's all we have been. I'm attached to his family, and honestly, being with someone for so long continuously starting at such a young age basically makes them apart of you. You both grew together, maturing off of one another. I just need advice. Would it be wrong of me to dump him? Because if I don't get the courage to, I might just suck it up and never do it.