my mother is actually the type to do this, where she acts kind when she is with someone and as soon as they leave she complains about them. (I dont care if you think what she does is cowardly I think its rude if you point stuff you dont like in front of someone cause it can hurt their feelings, I think she is being polite and honestly you shouldnt do anything to get her to complain about in the first place) but honestly its just a persons personality. it wont change, the best you can do is get on their good side. but if they are complaining about dumb stuff (like your job or things you cant change or dont want to for whatever reason) just ignore it.

Whoever is telling you they are talking about you is the person to deal with. Why would they do this ? Either they defend you in your absence or not tell you at all. Sometimes ignorance is bliss...

depends on who you are, who you're with and what you want the outcome to be. Personally if it were me I really wouldn't care, if they wanna talk about me behind my back they're obviously pathetic and weak and haven't got the balls to say it to my face. Those type of people I don't care if they're in my life or not. I'll be civil sure but i won't make any effort to impress them, see them or go out of my way for anything on their behalf Maybe try talking to your partner about it. I can't help you with what to say cos I'm very open with mine and I'd just say "your parents are talking about me behind my back" although she wouldn't be surprised or care either. Other than that, see it as their problem not yours and carry on with your life as normal