I have a lot of answers but I'll go with this one..
1) Because I greatly underestimated the joys of autonomy. IMO being single is a lot like being self-employed (and now I'm both!!) You don't need to be lonely as a single person anymore than you need to be broke as a self-employed person. I think both things seem scarier to contemplate when you're raising young children and maybe that is a lot of what kept me stuck. I am sure as sh*t that due to my sad tendencies towards procrastination/over-thinking combined or contrasted with my tendencies towards irrational exuberance/having eyes bigger than my belly, I shall experience many days, weeks, months in the future of pathetically low cash and sex flow. However, I am equally sure that because I'm a woman in her power moving freely through the universe there are going to be days, weeks, months when I am just rolling naked in the clover with joy and plenty.
"Tell me, what is it you plan to do with your one wild and precious life?" - Mary Oliver