letting go

I heard so many advice from everyone after the break up of my marriage. The most common one is to let go.   Its the hardest thing for me to do. Even now knowing my husband love someone else, I still love him and would wish him well. My friends say to just forget, to stay busy, be more active in the community, do what I love for me. I did that, I've exhausted and immersed myself to anything I should be so tired when my head hits the pillow. Not the case here, my mind still goes back to him. It irks me to see him acts so unaffected by his actions. I wish for a time when I don't love him anymore so I can finally move on. Why this constant thought of him, why can't I just hate what he did and let go. Have I really became so dependent on him that I forgot how to be happy without him? Or is it just my ego that has been badly damaged by his disrespect? I can't seem to follow the same advice I gave to friends in similar situation, I never thought this would happen to us. Only proves we are never in charged of our destinies. I have so much pain inside I don't know what to do with it. I hurt so much that it makes it painful to breath. I had always thought he loved me more, that I'm secure in the love he had for me, that we are to grow old together in love. Dreams are shattered because of his selfishness. Letting go, should be easy to do with someone who already left but somehow its not.