<human>: Disclaimer: I've seen similar posts but none that fit exactly my situation.  If I've missed one with answers to my questions feel free to send me to that post.

I've been dating my girlfriend for two years and for all intents and purposes it's a great relationship.  We never fight (I think we've fought twice in the 24 months we've dated), she's beautiful, we get along great, can spend days with each other without getting sick of each other, she's smart, ambitious, fun, I could go on but she's everything that any guy would want, and I mean it.  

There's absolutely nothing wrong with her or the relationship except for the fact that I am not in love with her anymore.  I've known for a few months but haven't had the balls to do anything about it.  She is the sweetest girl and I care deeply about her (which is why I want to do this sooner rather than later) and don't want to break her heart.  I know many people say I just have to do it (similar to ripping off a band-aid) but I don't know how to bring it up.  It's like I can say it in the middle of a big fight or because she does something that upsets me.  How do I bring up the fact that I love her but I'm not in love with her (ie, don't want to get married) with absolutely zero warning?

Can you provide a brief overview of the text?
<bot>: Perfect girlfriend in every way but I'm not in love with her.  How do I break up with her out of no where after two years?