The running on auto pilot is normal. I left my ExH after 13 years of marriage. The relief at not having to figure out his mood when I heard the key in the lock was fantastic. But, even though I was working (we had no DC) and had many people to talk to at work it was still lonely.
Then I decided I had to come clean with people. So I told them we had split and why. I have a theory that, because I'd 'emptied' everything out about him I slowly stopped missing him. Plus, of course, I had begun to enjoy the luxury of being on my own. I enjoyed making my own decisions and living with the outcome rather than knowing that he was controlling everything (and being the dim wit twat that he was, was making a balls up of all of it), seeing who I wanted to, when I wanted to.
But still I carried on answering text messages, picking up the phone when he rang. Then, one day, I was having lunch with a friend of mine. When I looked at my phone later I had missed over half a dozen calls from him. Each one more abusive (because, of course, I should have been listening for his calls shouldn't I?). That decided me and I saw a divorce solicitor that week.
It took me three years to get from moving out to seeing the solicitor - if exH hadn't made those calls I would probably have drifted along taking his calls and texts for years more. But I finally realised I was worth much, much more. My divorce took a year to come through. He didn't contest it but I was in no rush and I didn't want to antagonise him - not knowing how far I could push and with the advice of the solicitor we just went softly, softly.
A couple of months after my divorce came through I met my DH. We married and had our DS. My life sometimes feels like it's gone through a revolving door - dark on one side, light on the other. My DH is the exact opposite to my ex. Easy going, supportive, even tempered and my friend.
But it was hard. At first it was bloody hard. These people grind you down so much you don't trust yourself to cope. You HAVE to trust yourself. Whatever else you do you have to believe you can do something. Only you can change your future. Going back only takes you into the past. If that wasn't good this time round it won't be better next time. Try to tell yourself to keep moving forward. It will feel like you're pulling a huge weight at first but, believe me, the weight will get lighter as you realise YOU make the decisions, YOU have the power to make your own future and your DCs future a good one. When you get out the other side of this you will feel different - stronger, more self belief, and most of all happier. And you deserve that.
I left my ex 18 years ago. It's been a journey but it's been worth every step and your journey will be too. Just trust yourself. You can do this.