I think that if it gives you peace and happiness you should move on and file for divorce. Life is too short to stay in a bad relationship no matter how long it has gone on. Just make sure that you will be happy with your decision so as to not throw regret into the other feelings you are already experiencing.
You should do what you think will make you happy. If you are miserable in your marriage then why stay? It will be hard at first but you will be able to get through this. Dont let anyone bring you down!