Just out of curiosity, OP, how do you usually behave around your MIL that she could possibly construe as rude and disrespectful?
If you were to read all 12,000 of my DIS posts (go ahead, I'll wait) you'd find I have a very active, very developed sense of humor.

I grew up with teasing and ribbing and good natured fun from my own family. MIL has said in the past that's one of the things she dearly loves about me.
There has always been a bit of tension. Dh's parents were divorced. There was a lot of playing one against the other. Lots of decisions that I didn't understand, but whatever, that was her life.
There was a disagreement this last August where she had promised to do something very important for us to help us out. And then came back a week later and said no, she wouldn't do it. I got a little ticked b/c we had counted on her and "I experienced her as wishy-washy." (NO, I did not SAY that, but in light of the current situation, it's pretty funny)
We went to visit (FL) in November and had a LOVELY time (or so I thought)
Apparently she still felt there was tension. She emailed me and begged me to be honest, was there any more problems, was there anything bugging me, that she didn't want anything to still be between us.
So I mentioned one little thing. And she flew off the handle and went into all of the "comments made here and there during the trip" that she chose to ignore. ????????????? I told her that I wished she had brought them up at the time b/c I'm sure any comment I made was probably with humor. She refuses to tell me ANY of the comments made so I have no way to even defend myself. I think one of them MAY have been (assuming here) when we sat down at the movie, I happened to be sitting by her and I leaned over to dh who was about 4 ppl away and laughed and said "uh...can I switch with you so I don't have to sit by your mom?" then I looked at her, laughed, said I was just kidding, and we had a pleasant talk and watched the movie. I have NO idea if this is one of my "rude and disrespectful comments b/c she won't tell. But this is the kind of comments I make. I have done it for the 18 yrs I've known her and she has told me it's one of the things she loves about me.
I dunno. This ticks me off too. She and I (via email) said we're leaving the dh's out of this. That this was between
ME and HER. Dh is SUPER busy this time of year and doesn't need to be drug down by his mother who then requires lots of time with all of her needs. Besides, this truly was between me and her, so no need to drag dh's into it. Well, I had NO choice b/c dh called to say he was on his way home yesterday and he could tell I had been crying. But what TICKS ME OFF is that she had called his cell phone and left a message to the effect of "I know I'm not supposed to tell, but I just wanted to let you know that I think the relationship is over and yada yada yada big long message." UGH. Makes ME want to call HER dh (third marriage) and drag him in. She had NO right to break the trust.
UGH. So, yes, there were some precipitating factors. She begged me to be honest, so I was. I guess it's a matter of "SHE CAN'T HANDLE THE TRUTH." And no amount of niceties could fix it. SHE has chosen to end the relationship. B/c ever email I send now is not responded to.
I experience her as controlling, manipulative, unforgiving, and unable to keep a promise.
