Your erection failure has nothing to do with amount of love you have for your wife. Men can get erection without loving the woman he sleeps with, so erection and love has no connection. Your problem is related to your mental state during the act. During the act if you are flooded with negative emotions, anxiety etc then you may lose erection. Try to discuss the emotional issues running in your mind and sort out the solutions. Learn relaxation techniques like progressive muscle relaxation, Shabasan, Meditation, self hypnosis etc. Explain your wife not to put performance pressure on you, which can worsen your problem. Make her to read this answer.