Sorry to say, you have already hurt her.
You need to be honest so she can move on - if you pretend to love her when you dont, you are stopping her from moving on and having a relationship with someone who loves her back equally, not just sticking around because he's scared to be alone.
Be kind but honest. Apologise for leading her on for so long. Id cry all night too if i wasted 3.5 years on a guy who didnt love me back - unrequited love SUCKS. It is not self pitying to be upset about that!
Please dont jump into another relationship too soon - sounds like you might be better single for a while. You sound like you're just as needy as you say she is -concentrate on developing FRIENDSHIPS first, if you can maintain a few of them for a while, then you might just be able to have a healthy romantic relationship.
Wishing you and her all the best
Sky