JA herself, remained friends with Madam Lefroy after the Tom Lefroy episode passed into history so I think your impression may be correct that people had a slightly different attitude than we do today when two people part. I think it would also be fair to say that today people, young or otherwise, shall we say get “more” into relationships before marriage than they did during the Regency era and therefore may feel they have perhaps lost more in consequence if the attachment does not work out and the ending is then more volatile. From what I can tell about the Regency and this subject from JA, I think attachments usually did not progress so far and from most of the examples JA gives us it seems that the couple in question often are even in doubt of each others affections—indeed, they are all politeness most of the time.

In Persuasion there are three examples of attachments which do not work out. Anne and Charles remain on excellent terms although she refused his offer of marriage and his family even occasionally indulges in the wish that she had accepted him but they still treat her with kindness and count her among their friends. I am positive that all between Anne and Charles was polite and proper so when it all came to naught it was easily gotten over. Mr. Elliot and Elizabeth are completely an opposite as she resents his marrying someone else, but not as much as disparaging his blood of course, as far as he is concerned he might feel there was never any commitment there at all and it was all just a figment of Sir Walter’s and Elizabeth’s imagination. Just how many invitations and encouragements must you ignore befor a point is taken? Since I am inclined to agree with Mr. Elliot’s point of view in that it was only a figment I am very sure that all interaction that there was between them was polite, elegant, and proper and although disappointed, Elizabeth has no hysterics and Mr. Elliot just ignores her which has basically been their relationship all along.

“They had no conversation together, no intercourse but what the commonest civility required. Once so much to each other! Now nothing! There had been a time, when of all the large party now filling the drawing-room at Uppercross, they would have found it most difficult to cease to speak to one another. With the exception, perhaps, of Admiral and Mrs. Croft, who seemed particularly attached and happy, (Anne could allow no other exception even among the married couples), there could have been no two hearts so open, no tastes so similar, no feelings so in unison, no countenances so beloved. Now they were as strangers; nay, worse than strangers, for they could never become acquainted. It was a perpetual estrangement.” (Chapter 8)

When Anne and Frederick fall apart he does leave angry, he is not persuaded that it is for his benefit too and he is still angry and resentful seven years later. Anne is broken hearted, looses her bloom and is more or less in hibernation until he returns to awaken her. I think Anne and Frederick prove your point because in a very short time they came to know each other and, in a sense Mr. Collins will never understand, were violently in love with each other, therefore the breaking of the engagement was felt very deeply by both. On his return Anne wishes to avoid meeting him as long as possible, especially at Kellynch where there are so many fond memories and she is worried about how she will be able to handle seeing him. He is coldly polite to her and makes himself agreeable to others right in front of her and says mean things about her appearance to her sister. Yet, Anne is a favorite of Mrs. Croft’s and seems to be well liked by the Admiral while Anne holds them in highest regard, going so far as to think Kellynch is now in better hands than its owner. Frederick although angry still with Anne, likes Charles Musgrove, her brother in-law and does what is difficult to do, be polite to Marry.