Perhaps he is…a little. You broke up with him because you had too much going on. Not to be a bad person, but that sounds kind of jacked up. You basically said, “I like you, but my job is requiring a lot of me right so something’s got to give, and that is going to be you.”
You told him that he was less important than something else. While it may be true, it’s quite extreme to break it off for that purpose. Maybe your job is that stressful, and you did the right thing. But it’s a bit ridiculous for you to think that he’d just be okay with it and want to be your buddy the next day. Hell, you said you’re too busy for him but you still want him to be around the way you want him to? You don’t want him to be able to make demands on your time, but you still hope he wants to talk when you have time or hang out? That’s a bit selfish, no?
Going after your best friend is a hurt/desperation move. He knows it. You know it. She knows it. If she’s smart (and a good friend) she’d stop him in his tracks and tell him about himself and not allow anything to develop. He’s being a jerk there but he’s hurt. No excuses, just an explanation. Hopefully he’ll come to his senses and ease up on that but you need to do the same and realize that you broke up with him. If he doesn’t want to deal with you, that’s your own fault.