I want to break up with my boyfriend. Should I, and how do I do it?

Me and my boyfriend are both young (by that, I mean early 20s). I started dating him because he was my best friend and I was attracted to him. Sometimes I still am, but I find that I’m more and more annoyed with his behavior and stopped being a good girlfriend to him long ago… No, I’m not proud of it. He, however, is still in love with me.

Breaking up with him would seem heartless, because it’s almost like I have no reason to. I know it would break his heart. He’s not physically or emotionally abusive. He almost always thinks about me and is incredibly sweet. It’s more like I’m just not attracted to him the same way I used to be. We’ve both changed over the years, I’m not the same person I used to be. I get too easily irritated by his behavior and find I’m happier when he’s not around, and that’s not healthy for either of us.

There’s also the fact that before we started dating, I started to become friends with his friends and eventually, they became my primary social group. I don’t really socialize outside of this group, which wasn’t a problem until I considered breaking up. They were his friends first, and I can’t expect them to still want to associate with me if I break up with him. If I’m lucky, I might stay in contact with 1 or 2, but I know that I will never be included in our group outings again.

I just want things to go back to the way they used to be, when we were all just friends but no one was dating each other. I know that’s idealistic, but I feel like I’m trapped, and I don’t know what to do. Break ups are always so, so hard, but this one has a lot on the line. I feel like my options are either to give up my best friend (current boyfriend) and all my other friends just so I can date other people, or to condemn us both to a one-sided relationship. And even if I decided to break it off, I don’t even know HOW to. Please, please help.

Side note, I posted this on Quora and got no help. The only advice I got was to break off all contact with anyone associated with him, but I’m not cold enough for that. I’m really looking for some support!