Alison, I have experienced the pain and sadness of a relationship that came to an end, and like you I could only see good in him although I knew he had behaved badly, ultimately those feelings delay your chance of coming to terms with the end of the realtionship.
The loss of a relationship is a grieveing process which will end in time, things will get better but for now use the forum and your close friends to help you through, writing your feelings down helps and using some self help books will help you to understand your feelings. Accept the feelings you have but in the meantime be good to yourself, take carex