I think you need to stop prioritising stroking his ego - because in reality it sounds like you don’t actually think he is doing so great That he deserves constant praise - you’re lying to him, telling him how much you appreciate what he does.
I think you guys need counselling. You have lost respect for him. The contempt is clear in your posts. You don’t want to have sex with him anymore. You’re so angry it’s starting to affect you that you’ve snapped in the car.
You actually sound depressed to me - because I had snapping rages like that when I was depressed.
You sound like you didn’t intend to become the breadwinner, it just happened. This isn’t the life you want for yourself. You sound miserable & in your situation I would be too. I don’t personally respect anybody who just unilaterally decides to stop working after their kids start school. That kind of lifestyle is a luxury.
Him being the SAHP is not working, it only works when both parents are on board. You’re not on board. Things need to change - but you also feel he is so lazy you will have to organise his career for him, while managing your own too! He sounds like a drain to you.
The $600 item - you’re upset because that was money you earned & rightly or wrongly you feel like he frittered the money away without researching or making a good decision about the new purchase.
If you were a bloke you would be 3-6 months away from shagging they office girl & imploding you’re family life.
Don’t do that - communicate & counsel together. Be honest with him how this resentment has eaten you up.
He is not the same person he was, but neither are you most likely - you’re worn down & he needs to step up & get out to work.
You’re setting yourself Up for a divorce which is unfavourable you you financially. He will get custody of the children & he will take half your super & the majority of the house as he is the SAHP.
This isn’t want you agreed upon - he changes or end it before you have a nervous breakdown & have an affair or something else destructive.