<human>: Can you give me the gist of the text in a nutshell?

Long story short, the "in love" romantic feelings I had for my girlfriend starting fading about 3 months ago; however, I still really care about her and love her as a friend.  Things have been as good as ever between us.  I'm happy with my life and I don't have any urge to break up with her at all.  

Lately though, she's been talking about our future together, and I'm given pause.  The fact that I'm not actually in love with her has started really bothering me; I realized that I'm basically lying to her by maintaining our relationship.

How do I bring things up with her?  I really don't to let go of someone so close to me, but that's just selfishness on my part.  She deserves to know.  And to be clear, there is no one else in my life that I have feelings for.
<bot>: I still love my girlfriend and really care about her, but I just don't feel like I'm "in love" with her anymore.  How do I proceed?