Why does love hurt?

Why do we fall in love? When the love is returned and it is never taken for granted it can be the most amazing thing in the world. But when something goes wrong, you are left feeling completely broken. I'm really struggling with my break up lately. I find myself looking at old pictures of us and remembering all the good times we have had together. How in love we were. He was my entire world - along with Lilia, of course - and I would have done anything for him. He made me so happy, I belonged in his arms and there was no place I would rather have been. He is still my world, in a way. I still have all the feelings for him that I had back when we first got together, I guess that's why I'm struggling so much. When things remind me of him I get so upset and end up re-living all of our amazing memories. It breaks my heart knowing that we took advantage of this amazing love we had between us. That we used and abused it so much that it ended in heart break. He has given me the best gifts anyone could ever give me - my beautiful babies - and no one can take that from him. He is my one and only first love, and always will be. Nothing and no one can replace him or what he is to me. He is my first love, the father to my children, the one who made me a better person, the one who helped me through a lot, the one who showed me a lot and taught me a lot more than anyone else ever could/can. I don't know where I would be if James and I didn't get together. I will always have feelings for him, and it's sad that they can't be put to use. Every day I long to be in his arms, to kiss his lips, to tell him I love him. When we talk about Lilia or Tyler I find myself aching to tell him I love him; to beg for him back, tell him I miss him, etc.. But I don't. I don't want to complicate things any more than they already are. I have no idea what is happening with us so I assume he doesn't either. We need to have a serious talk about it, but it's plucking up the courage to start that talk.. It's too painful to talk about how much I love him when we are not together. How I miss him and I cuddle his pillow and his side of the bed now that it's empty.. It's so embarrassing, because everyone tells me I shouldn't love him and I am better without him. But still I want him. I don't know why - if I could not love him I would. But I can't. I am drawn to him. He is like my drug, even though we are complete opposites. Like the saying in Twilight goes "and so the lion fell in love with the lamb". In this case it's the lamb loving the lion, but same concept.. Hmmm. Sorry, this is a pretty pointless post to most and some of you will probably find me pathetic. I just needed to get things off my chest. I've had an emotional day, I've pretty much been crying all night for various reasons.. The main one being me missing James. Love hurts. Nothing will change that whether you are with the one you love or not. Sadly. It's just the way it is.