me and my fiance do have a bit of banter in front of people but we never get personal or put each other down big time. my fiance knows i love him and wouldnt be without him it's just some banter the same way i do with my best mate and my brother etc
I would say most of the time it is light hearted banter or flirting between couples, but if it is not as nice as that, perhaps these people have just got to the stage in their relationship where they are comfortable enough to point out each others faults!
i blame the sitcoms myself, virtully every couple featured spend their time running the other down for a laugh - sitcoms are so endemic that they have convinced people that that is the correct way to behave as a couple - that's my theory anyway!
Mr CP does it to me all the time, but thats cos he is insecure and is fully aware that without me he is nothing! and, when he continues to do it in public he gets 'THE LOOK' and i continue to blank him for the rest of the evening, and possibly the week, plus, MY put down one-liners towards him are far far superior, and joking i am not!