You can very well be grieving for a relationship with your wife as well. this does come at a price but remember that you are not giving up your family. You are simply giving up the marriage. Be very sure if this is what you want and work from there.
This is very complicated but so is any relationship when you separate. You would do well in counseling before you make your decision to deal with the anxiety, depression and hopelessness. It could benefit in many ways.