I left my selfish, lazy, narc exH almost 10 years ago (that's gone quick!) At the time we'd lost a ton of money on the house we bought with all my deposit money (my lovely terraced house wasn't good enough for him) and if we divorced I would have potentially lost all the money I'd worked hard to put in. thank you housing crash of 2007/8.
After 4 years I couldn't take it any more and kicked him out. At first he refused to leave, then when he did go, he kept coming back every few days, talking about how upset, sad this was making him, not once asking me how I was. I knew then that I was completely validated in ending the relationship.
Eventually he stopped coming round, I managed to get a new job and was able to remortgage the house in my name and started divorce proceedings.
Don't look back. It's OK to be sad for what could have been but keep moving forwards for both you and your DC.
If it helps, I had a good 2 years being single and thoroughly enjoying it, and then met my DH who is entirely perfect in every way and we got married and have our DD. Things work out in the end OP, if you let them. Set your goal initially to being OK with being single. With accepting you are enough. When you're happy with being single, then you're ready to date again. Don't rush into another relationship until you love yourself and are much pickier. Trust me.