I was exactly like you before I decided to file my divorce. Once you made up the decision and finally file the petition. You will be cleared you mind and you will need to concentrate to deal with your solicitor. You need to fight what you and your kid's best interest and what you are entitled to - Custody and most important Maintenance for you and your kid. Trust me, I just have been thru all of these.
Be strong, it is not the end of world. It's his lost not you!!