U, I feel you handled the conversation well. It is natural to be depressed when something like this actually happens even if you had an idea it was going to happen. We go through a grieving process and it takes time to heal. Expect to have emotional ups and downs and know that however hard it may seem, you will heal and feel better over time. One piece of advice is to not look back and wonder "what if". WAS say a lot of things that make us feel like we could have saved the marriage if we had done something different. Over the course of a year I addressed a lot of the grievances that my ex had but in the end she always found some reason to justify her decision. So, don't think back about what you could have done to save the marriage or "win her back". Focus on what needs to be done going forward.
This is my opinion, but I feel that filing may actually work out better for you given your current sitch. Based on your posts, it appeared the MR was dead and your W was not motivated to try to R. You were already separated and the financial & custody terms did not seem favorable to you. Made me wonder what was preventing you from filing since you seemed to have all the disadvantages of being D without a lot of the benefits.
Read the posts by the others above, there is some good advice there especially about having a good lawyer to represent you.
You have come a long way since your first few posts and I have seen you grow over the months. Focus on your kids and take care of yourself. Stay strong my friend, it will get better!
