The grass isnt always greener, but it has got to be greener than yours in most cases OP. You are completely settling.
I got no grand proposal either. But I'd have been mortified if there was anything in front of anyone.
I work 28 hours as well. That's 80% of the working week so doesnt mean you fit 100% of the housework into your day off! My husband does half the housework, half the childcare, probably more than half the school pick ups and drop offs, he gives me a lie in most days as he is a naturally early riser, helped in the night when they were babies even though I was breastfeeding etc etc. The whole 'he is a man and they think differently...well yours does but I know loads that don't.
If you were single you wouldnt be holding on to this resentment, you'd be free to date someone who actually added to your life, you would have one less person to cook for and clean up after and if he wanted contact time with the kids youd have regular time off and lie ins etc
What would he say if you said you were sick of getting up early and you wanted him to take turns? And put ear plugs in and feigned sleep when the inevitable 'I'm tired / I didn't hear the kids get up' happened? When you said you were sick of doing all the chores or washing or whatever and if he didnt do his share you wont be doing hi any more?
You sound really ground down and passive, I don't think the low self esteem was just when you were young, you seem to think this is a typical marriage, a shit marriage is better than no marriage, that you somehow deserve this and all men are like that anyway, and you couldn't be happier on your own or someone else. None of that is true at all. Could you look into therapy or counselling to explore why you have accepted a shit situation for so long?