What I need to do is convince myself to believe wholeheartedly that my contribution to the family (non-monetary) has an equal financial value.
Once you get started on thinking about this, you'll soon see that you probably contributed more - much more than you realise. To get you started:
You said earlier that your H never shopped with the kids. Ever. So have a think about all the times that you sorted out their needs - all those hours (days!) going into shops and trying on stuff. Petrol money to get you all there and back. And think about where the money primarily came from.
You also said that you had to remind him that there was no food in the house on his days - so you do all the grocery too, right? Household consumables like showergel and all that? Who shops around for the car insurance, or books the kids into the dentist and takes them there?
Who sorts all the holidays? The holiday clothes? The school books and uniforms and the envelope with the right amount of cash for music/ swimming/ voluntary contributions? Playdates and birthday gifts?
So you see, while I earn 10k or so less than DH, and the actual household chores are 50/50, I more than match his extra income by being the family PA. In fact, I'd go so far as to say that my contribution is incalculable, such is it's value!
Go for what you are entitled to. Fuck being 'fair'. His idea of fairness and yours will never meet in the middle. If you left with only the clothes on your back, he'd probably insist that he bought those too and what a money grabbing bitch you are. So if you are going to be painted as a money grabbing bitch, you might as well earn the title fair and square.