I’d say it was already in the works with his new g/f within 2 weeks. It’s a sad case but people do fall out of love or infatuation or w/e the relationship gives them. What reason did he give at the time he told her of the breakup status change. Daughter should also give herself pause to think about her own needs in this or any future relationship and see herself not as a broken person from this relationship. If he’s that quick to fly to another branch with another g/f already exactly what did she lose? Sounds like saved herself from future heartache and trauma is my slant on the facts you state.

It doesn't sound crazy to me. I dread the time in a few years when my daughter starts dating and gets her heart broken. Back in our day, a girl might not have known her ex was with someone else, because there was no social media. Everything is in your face now and it's mostly faked happiness. I hope she has hobbies, pets, and activities to keep her busy.

She’s 14 and all her outings with this boy were chaperoned and supervised. His mother and I were on the same page about supervision, so that part was good.
Social media is absolutely a killer because, as you pointed out, it’s all in your face. Snap chat and Instagram are the current tools to torture.

she is only 14 and probably still figuring out about her own identity (who she wants to be, who she feels comfortable being) and what her needs/wants/preferences are and so its natural that first couple of relationship will be rocky and most likely fall through. [ like testing the water, not only about getting to know about her interest (boyfriend) but also finding more about herself through others(her own limits, personal traits, beliefs etc..) ]
After this relationship, she will be that much more clear about herself and what she wants and doesn't want in a relationship which can be used as a stepping stone for her next relationship.
She shouldn't feel hurry to get into another relationship so soon as she is still so young and there are people everywhere so its only a matter of time she finds herself in another relationship. In mean time, she should focus on herself, her beliefs, value, standards, preferences etc.. and look for a relationship that are in line (or reflects) who she is.

you are dangerously codependent. She has her feelings : you need to have yours. She has her boyfriends : you need to have yours.

Don't blur the lines. This was her boyfriend not your boyfriend.

Don’t think I’m “dangerously co-dependent”, merely hurting for my kid. I have my own boyfriend, my husband of 29 years. My kid is sensitive and when she hurts, I hurt.

That's what being codependent is all about. Not having your own reactions to things, having theirs. Buying into their point of view over your own.

You have to have your own reactions to things. Otherwise your confirmations of her reactions will feed her false view of reality, and you'll develop a kind of hysteria between yourself and her that escalates and becomes very unhealthy.

The bottom line is she went on a few supervised playdates with some kid. He didn't want to be her 'boyfriend' and moved on.

Well this was always going to happen. Her being hurt was a given. So it's just fodder for maturation now. It's just something a philosophical mother needs to take a step back from and say 'well there you go, that happened.'

And teach her some skills for taking a step back herself.