..This is why I do not like it when girls keep contact with their ex boyfriends. I know with a lot of girls, they do not talk to them anymore, but some of them hang on strong to their ex's and when they get involved with another man..they start missing their ex boyfriends even more and eventually go back to them.
From my perspective it is not something the 'new guy' did.. it is something most girls do - they get with a guy to 'hold them over' while they sort their feelings out with their ex boyfriend...
Your message was ok IMO, it was mature. It could not been me though, I probably would have got very angry, seeing as that kind of thing used to happen to me all the time. I don't mess with girls anymore and prefer to be single.
People have histories, lives, and a mature individual will realize that. Relationships change, but it doesn't mean that one immediately stops caring. While the intensity of feelings can change, they are still there. It's normal.
You care about people you were intimate with. Especially if the relationship was over a period of time.
From my perspective, it is the OP's fault. If he wanted her to know she was more than just someone to copulate with, he should have taken her out and spent some quality time getting to know the rest of her. He got what he wanted, nookie without the work. I don't blame her, either, I like to think I am worth much more than just six.
Like walks in the park, dates, movies, picnics, brunch, attending concerts, sporting events, learning about me while I learn about you. I am worth the effort, and I bet she was too.
Harsh but true, OP. I am a woman. Treat the next one better.