I believe that the question of whether we're capable of loving again varies by person. It sounds as though you had your person. The one you were meant to be with. I hate to say it, but you will likely never love that deeply again. I know the feeling. You can try to love again, but never expect anything to feel like it felt with him.
But you must be strong. We are warriors. We must bury our sorrow and focus on what we were born to be.