I have been there, including the PND
Have been very close to leaving when DC were babies/tots.
I remember getting very angry one night and throwing the whole pile of dishes on the floor. I had spent the whole day entertaining tot and breastfeeding baby, cooked dinner, and after dinner DH put his feet up and started getting ready for his hobby.
I was standing in the kitchen, running the water for washing up, and a red mist descended. I swiped all the plates onto the floor and screamed :"Fuck this, I am leaving you!"
DH was super shocked, very upset and worried and had no idea I was that angry about his selfish behaviour.
We have had to renegotiate our relationship on an ongoing basis.
It was not perfect, and the selfish behaviour kept (keeps) cropping up at irregular intervals...but I call him up on it, and he listens. I have maybe become more "selfish" myself to balance things 
The thing is though, we were always able to talk about it, we could always somehow still find the humour, and there was always still affection. DH also tells me he loves me, and does little things like making me tea in my favourite mug every morning.
Those little things, small moments of affection and having a laugh seem to have kept us together through rocky patches.
But smashing those plates was necessary to start a whole new relationship.
You need to talk, you need to get angry, ... and he needs to listen.
You need to fight for yourself, and for your marriage (if it is worth it!)