If a couple are having problems, is this bad for the child? there is a long explanation, sorry but please help?

It sounds like you want to give your mom an ultimatum. I don't think that's such a good idea. For one, if you do that and she tells your step dad it will probably cause another fight and possibly make him resent your sister, if he doesn't already. You may want to tell your mom how you feel and how her attitude is affecting you mentally. Also tell her about the negative impact it's having on your personal life,such as school and so forth.Then explain to her what YOU must do to improve your quality of life. After you've done that, then ball will be in her court. She will have to make the decision on how to proceed with her relationship with you, your sister and her @sshole husband T you haven't given her an ultimatum. It's been my experience that ultimatums don't go over very well. Now lets see about your second question. I'm not a pro but I would bet that you and your sister have a dysfunctional family. I believe that growing up in a situation like that has to have an negative affect on you sister. But on the other hand I'm sure the type of personality she has does have an affect on how she will turn out. If you grow up around something all your life more than likely you will repeat the same behavior. I'm sure some people don't. I think it's due to personality and a stronger sense of right and wrong. I too was in a similar situation growing up, but this not about me. Hope I was able to help.......or at least give you something to think about. Good luck! L8TR