I think our divorce was a mistake

[Just_Me]

In my heart and based on his behavior, I know that this was a mistake and I don't know what to do to keep him in my life because we have no children and no other connections

You need to remember that this is your interpretation and it's skewed by your own feelings. Yes, he held your hand and he talked to you like an old friend, but that doesn't mean he isn't happy to be divorced. He wanted this, remember? So, what can you do? Move forward with your life. Make the most of this time being single. If he desires something else than divorce he'll let you know. Give it a couple weeks. See what he does. If there is no contact, then touch base with him. If nothing comes of it, then figure he's not interested, the same as you would any person, and move to the next. What have you done in the past when you've broken up with a boyfriend? Did you keep chasing him and find success? Or did you move on to someone else? Divorce isn't that different. It's HIS responsibility to foster a relationship if there is going to be one. You can encourage it when he initiates by being receptive, but you can't make it happen by chasing after him.

Me