How do you break up with someone who is completely in love with you?

It’s been complicated from the get go (too much to explain). Now about 3 years later things have finally settled down to where we can just enjoy each other. However, as much as I like and enjoy having her around (and I DO), I’ve never felt “in love” with her.
I ended my last relationship too hastily, resulting in a lot of unanswered questions, regret, and subsequent (and continued) doubting my own thoughts on such matters. To make matters worse, if I ask myself if I want her around, the answer is yes. But if I ask myself if I want to date her, the answer is I don’t know/maybe/I don’t think so/yes/no/I have no idea… and there in lies the problem. All my friends tell me I should break up with her because she’s completely infatuated/in love with me and I’m not with her. But, how do/can you dump someone who truly loves you unconditionally, who hasn’t wronged you in any way, and who is fun/nice to be around, but whom YOU (for some reason?) just aren’t in love with?

On a side note, could it be that my not being in love with her is merely a matter of something like me being overly picky and just not letting myself?