<human>: Can you condense the text into three sentences or less?

I've currently been in a relationship for coming up to 18 months with my GF (17/F). I, however, think I'm falling for one of my friends. 

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In my current relationship, which was also my first, I go through stages of feeling like I love her, and yet don't. I mean, she's extremely clingy and gets jealous when I end up talking to another girl despite them just being a friend or talking to them as they're in my class. She even asks me who else I find attractive so that she can 'dye their hair grey' and says other things of the sort. She says things like she wants to marry me and have children with me too, but the thing is, I'm not even sure as to what I want family-wise in life, and it feels like it's being pushed onto me. Don't get me wrong, she's sweet and all, but some things she says and does just kind of, weird me out a bit.

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The friend who I'm falling for is the same age as us, and is part of our so called 'Friendship Group'. I've had a crush on her for the better part of 5 years or so (I know, a long time). The thing is, I don't even know how she feels back. And I don't want to end things in my current relationship if I won't be able to make things work. She makes me laugh, and when I'm around her, she drives me crazy and I don't think it's fair on my current relationship that every time I'm around her, I treat my current GF like just a friend. 

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I've even gone as low as weighing things out with Pros and Cons of them both (mainly because of my recent 'Friends' marathon on Comedy Central). And what is holding me back the most, is just that I don't have the balls to break up with someone unless I have a clear reason too.
<bot>: Currently falling for one of my friends despite being in a relationship for 18 months and not sure what to do. Help.