You are a brave man. The boundary thing sounds easy but it's not, especially when you are in the same house. Maybe start with just one area/topic. Chances are you will find more success in that. You may want to consider not giving her cash. But paying the bill for her. It is more work for you - but it may help with the boundary and give you a little more power. If you give her cash she can buy what she wants not what she asked you for. Just an idea.
M:50 W:53 MR:20 D:21 S:17 S:11 BD-Sept 2015 Suspected PA Sept 2015-Confronted W & OM Dec 2015 Actually EA In house Sep:Jan/16-May 2016 W moved out:May 22 2016 OM-Intro Oct/17-On scene July/Aug 2017