Make it up to me

My ex broke up with me and it totally devastated me. Mainly because he did it out of the blue and never really told me why (he used the typical "It's not you, it's me"). For the past 10 months, I've been miserable and fighting to move on and last week he contacted me and told me that he had his life straightened out and wanted me back and that he was stupid for letting me go. We've been talking as friends and he said that he'd do anything to make it up to me if I would take him back and began a new relationship with him. I don't even know what could possibly be done to make it up to me. I do believe him that he's in a better place for a relationship, but I'm just scared of him leaving me out of the blue again. It took me so long and so many tears shed to heal the first time.