AIBU to have had enough of being the one person to whom all my family vent?

[Mummy2aRockstar]

Evening mumsnetters,
I've well and truly had enough tonight and wanted some opinions if I'm right to be peed off or this is my job as a mum and fiancé.

I seem to be the one person in my family everyone will vent to after a bad day. My 4 year old son will come home from school tired and grumpy and I'm the one to get the attitude (I do expect that tbh), then when I've finally got him either in bed or getting ready for bed my fiancé will come home in a grump.
Ok he works 12'hour days and sometimes longer and he's tired too but why should I get a stroppy teenager walk through the door to sit there sulking all night.
I get made out to be a nag when I do nothing of the sort, dinners always ready or cooking when he walks through the door, I let him watch what he wants or play on the PS4 and on his day off he gets the tv all day.

He's been off today and everything seemed to be my fault or result in eye rolls or a snappy response, he's 43 and rolled his eyes when I asked if he was joining me to pick up our son from school or staying home.

To add salt in the wound his mum will moan about him to me at any given opportunity rather than actually tell him.

So AIBU or can I rightly exploded like a peed off Vesuvius?