I'm turning 40 and split from my ex 2 years ago, 2 kids under 10. My life is 10x better than it was with him. I was so lonely, confused, tormented and abandoned in my marriage. He had 2 long-term affairs while I turned myself inside out trying to support him through his "depression". He entirely opted out of family life, and I was responsible for the house, the children, while working full-time with the vast majority of the financial responsibility.
I'm a different person now, I still get weekly therapy which is a major support to me. I do yoga weekly and go to the gym 3 times. I have so much more free time now as he has to take the kids. I'm never lonely. I was so lonely in my marriage, but never now. I have so many friends, a fulfilling career, and 2 great kids.
A relationship would add nothing to my life other than compromise and complexity. And I refuse to ever put my childrens security and happiness at risk. We do what we want to do, when we want to do it. My ex is passive and is happy to default all decisions/control to me which suits us both. Sex is a distant memory, and I can't imagine ever being intimate with another man - I don't know if that's a positive or a negative? And, I also think I don't have space in my head, my schedule, or my life for a man. The overwhelming feeling that I have is one of freedom and peace, I'll never jeopardize that again.
Last thing, feel lucky that you can get out. From my vantage point, a lot of my friends are in subpar relationships, getting by and compensating with other areas of their lives. A few have said they envy me the freedom to leave, and to not need my ex. If he never gave me money again, I'd be fine. I know not every woman has that independence.