Look at different ways of validating what she is saying. People don't often argue with someone who agrees with them, validating her position will help. Remember for every conversation you are just as guilty of the upcoming as her. Hold yourself accountable and whenever you argue, try a different tactic. It's not about being right, it's about doing what's right to get the right result.
Most importantly try not to talk only to respond, try to communicate.
Talk to me like someone you love, is a book I read on good validation techniques.
Me: 32 W: 29 T:8 M: 6 D4 S2 M - 8/2008 W is not happy - 1/2014 W wants D - 9/2014 W moved out - 11/2014 D filed - 1/23/2015 D'ed - 2/25/2015 Gave X the Letter - 11/10/2015