I would reach out and ask to see him. You two grew up together so there’s an enormous amount of history so I would hope because of that, he’d be willing to sit down and talk. Tell him everything you have said here. Then you listen because he’s shattered and you need to honor that. You didn’t do anything wrong but he still gets to be hurt. He may need some space but absolutely put your cards on the table. I think you start with… I made the biggest mistake of my life. You probably did need it though because it’s made it very clear that what you want is what you walked away from. You’ll regret it if you don’t try everything you can to just sit down and pour out your feelings.