Yes it is. Part of recovery for you is going to be learning to move on and be happy regardless of ever getting an answer. Another part will be not caring if there is an answer.
Take care. Most of us have been where you and understand, at some level, your pain.
The good news, however, is that he is your ex. Some gals on this board aren't so lucky.
Take care, take what you want, and leave the rest.
Cyranoak