How To Let Go?

How can I get over my ex once and for all??? I still feel emotionally attatched to my ex-fiance and my last boyfriend (we'll refer to my fiance as V, and my bf as L) But both of those relationships were a long time ago. And now somebody amazing has fallen in love with me (we'll call him T) and I can't love this person back until I completely let go of my ex. How can I do that??? How can I let go of V and L so I can take a chance with T?