Even if you really got back together with him, the relationship won’t be the same.
He just slapped his hand down on the big red ejection seat button for your relationship. Now he’s looking back at the plane he just left and is having second thoughts. That’s normal human behavior. But still, something made him press that button, which means that the relationship as it used to exist wasn’t working for him anymore.
So pretending all this never happened, even if you wanted to, isn’t an option. Your old relationship is gone. Maybe you can form a new sort of relationship that works for both of you, if both of you want to. But both of you would have to want to have the new relationship, and that doesn’t seem likely to happen.