You reminded me of my H and his family when you described your lunch/dinner habits. Belgians are like that, too. It made me smile.
I will leave the advice regarding OM to those who know, but will warn you that if she is saying things like "don't try to turn my family against me again" then she is sending you a message and I think you should be careful in your actions in that regard. From the way you described it, it sound as though her family were unhappy about her PA of their own accord, not because you said anything to them to turn them against her and yet she still thinks it was something you did.
I think it is human nature when someone close to us disapproves of something we know in our guts to be wrong to rationalize why our relatives are disapproving and you are the perfect scapegoat.
I will also tell you I have read enough posts here to feel pretty sure that whatever one says to inlaws will find its way to the spouse, so watch what you say. Lots of people here recommend DBing the inlaws right along with the spouse. I have had no contact with my inlaws sich H left and do not plan to for now. So long as I am not pursuing R with H, I will not pursue his parents. If I am not discussing R with H I will not discuss it with his parents should they contact me.
I had a good run today. At my peak I run about 16 miles per week - 10K every Saturday, 5K every Sunday and two more 5K's during the week. Since the separation, I have been struggling but I am fighting to get back to my peak. The endorphines are amazing. I posted earlier saying they only made me feel slightly better, but I was wrong. I feel a lot better.
Glad you are doing alright. I'll be around all weekend.