Why cry over spilled milk?
She wasn't a good match for you.
I think you took on the role of father and in fact you were only a bf. Then you were trying to tell your gf how to parent. You may be a teacher, but you sound like you have NO kids of your own. How can you tell someone how to parent their own children when 1. You are only dating and 2. You have NO children of your own.
I think you should leave the role of "teacher" in the classroom. This gf and her children shouldn't of been treated like pupils.
You come off a bit "high and mighty" and very critical. You probably are the type finding and correcting the faults of others and that my friend will keep you single.
Didn't you end things with her? Not sure why you are asking the question.
I think it is hard to jump on the band wagon of another parent's parenting and their kid's behavior when you are new to the picture. Who knows? Maybe the kids weren't thrilled about having you around and were acting out.
You were new to the situation and were trying to come in an authoritative way. Most psychologists would tell you to not play the father role with kids at this point (a new dating situation). That is generally ALWAYS going to end bad and had SHE written us, I'd have told her that it is not smart to bring dating partners in and out of kids lives because it is hard on them. This is an example of that.
I'm also about guiding kids, being positive rather than constantly critical and it sounds like you work from an opposite angle.
Anyway, this relationship is over and it sounds like it is for the better. good luck
If the relationship is over, I would not spend any more time worrying about it, her, her kids, or whether she has finally come around to your way of thinking and seen how correct your advice was. It's possible that you being around made things worse -- children don't usually react that well to Mommy having a boyfriend who is around at bedtime and telling them what to do. (Even if you were her husband, you would only be their stepdad, and a stepdad's primary power base is not authority but his ability to make the kids like him and want to please him.) Even if your presence didn't make things worse, and that was exactly how things were before you came along and is exactly how things are now, you're not a couple any more and you're not her husband. This means "I told you so" and "Have you seen the light?" are messages you don't get to say. I'm sorry.
How about being consistent with encouragements and expectations?