Thanks for your responses. Trying to make sense of it all, and he INSISTS on a friendship with me. I will have to interact with him regularly, as we have two small children.
I know that he is mentally ill, but obviously I cannot Google diagnose him. He definitely has "insecure attachment" with his most prominent symptom being abandonment issues, constant need for reassurance, and also validation. He suffered neglect and every kind of abuse including heavy criticism.
Please don't take my posts as me thinking I am perfect. I am in therapy and addressing my own issues.... I'm plenty reactive when I feel threatened, and we had some ugly arguments. There are definitely things I would have done differently had I known he was mentally ill. I didn't start really looking into it until this all happened. He's been plenty unstable since he broke the news to me. He looks like he's aged about 15 years, actually, and he's only 34.
His main reason for leaving was lack of "passion" so you're right there Anthony. We went to counseling last winter, and I was excited to start working on "us" as our children were out of the toddler stage. He was completely turned off by putting the "work" in. He just wanted the "passion" to happen. but he never told me. He just rolled over every night and buried his had in his computer, and then one morning over morning coffee told me he "couldn't do it anymore." Forget about all the family trips, hikes, bike rides.... he only ever wanted the simple super duper passionate relationship with me.
I have asked him to agree to initiate the divorce process because I have to protect my kids. He does not want custody and I would like to keep it that way. Of course he will still have access to them.
Yesterday told him we would not have a personal relationship, and I cannot be there for him until he gets help. Just because he enforces "small talk" with me on a regular basis, and it's exhausting!!! Well, tonight as he was leaving, he randomly spouted that he has "sessions booked all throughout next month". I said "okay". Not sure I believe him....
Why is he so insistent on maintaining a line of communication with me? now I feel like saying "good, share your findings with your new girlfriend."