Please just take this as a view from reading your post, things may be completely different in person or how it went down, but it seems you are being a little harsh or maybe rude...
Im not sure, I know you are stating your boundaries but sometimes it seems that you are trying to show control over her...I iknow it is difficult knowing what to do but maybe you could have asked for a moment to talk after she kept interrupting you and told her that you really get frustrated when she does that and you want to be able to communicate calmly with her, and then go on to answer her questions.
I have a feeling that when you clam up or walk away and not finish a conversation probably makes her feel worse towards you. There are ways of diffusing a situation at the time, given it has not gone overboard then walking away is probably right.
Again, just another way of looking at this and i may be completely off base. I wish i had all the answers as well.
M 37 W 34
T 12 M 8 D 7 S 4
Need break 4/12/15 W no ring 7/7/15
Separate room 4/12/15 Separate living suggested 8/15 W moved out 11/1/15