Scout, I agree w/OwnIt...you are definitely wise beyond your years and experience. You have to do what you think I right for you and your child. Do you sound bitter? No, you do not. You sound like a woman who has tried very hard to keep her marriage together and your partner wasn't in the marriage/relationship 100%.
Hopefully he will come forward and respond to your solicitor and things can begin to move along at a better pace for you. Once the divorce is finalized, you will feel a huge weight lifted off your shoulders and it will take a little bit of time, but you will much better and can begin to really look forward and not in the rear view mirror.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.