Namechanged as its so outing
Yesterday I was at my fiances parents house.
The mother's friends (a couple who i have met before) turned up as i was planning on going for a walk.
I made them both a coffee, sat and made polite chit chat alongside my DP and his family (going for my walk would have been rude apparently). When asked what we were up to my DP said we were getting a dog
The husband looked at him, then me, and said something like "why are you getting a dog - you've already got one sat next to you"
I sit there thinking okay not my house. I look at mil who laughs politely. DP says nothing.
The man's wife looks embarassed and said dont worry he often calls me a dog. Taking the dog for a walk ho ho ho etc. 
They then continue to chat while i am thinking WTAF
Insread of handing him his arse I (vairy fucking politely) get up and tell DP i am going for a walk.
This was around 4pm in the uk. I go for a walk to cool off and get space aiming for his aunt and uncles 30 mins away they arent dickheads are lovely and i know them well. Dp texts around 4.30 and i explain I'm fine but ballsed up directions. I do a detour meaning i arrive around 5.30.
Text to say i've arrived. Everyone knows my location. Even though i am an adult and it is not necessary
They say stay for dinner cousins have cooked. I do and we have a lovely time.
Ask dp if he wants to come over and see family and we can walk back. He is shitty with me and says hes been busy cooking "for guests"
I say fine, stay there I'll get a lift. Go back to chatting with aunt and return about 11.30pm
When j get bacl he is angry with ME because "anything could have happened" (his parents live in oldham not Basra)
I asked him "how exactly am i the arsehole in this situation?"
He said "well how am i?"
I told him i wasnt discussing it and he should go to sleep
WABU?
I felt i was quite calm and did not overreact