Start as you mean to go on - Never, ever place yourself at a lower priority behind everyone else and never, ever put up with being taken for granted. You count too, you are not a mummy martyr and a skivvy for everyone else. An empty, worn-out, resentful and sad mother will not have the resources needed to look after everyone. Someone needs to look after you too, and if no one else bothers then you need to tell them straight out and not just fall for empty promises but actually expect your voice to be heard and your needs to be met. Teach your daughters, by example, to value themselves! And teach your sons to value and appreciate everything you do.
Speak things exactly as you mean them - ‘I would like a card/small (or big) gift/chocolates/a special meal on my birthday; I would like x hours for my hobby/walks/gym/coffee shop per week - equivalent to any hours your OH takes without even giving it a second thought, just assuming that you will always pick up the slack; I would like you to be responsible for X Y and Z.
And again, don’t accept empty promises. Love is a verb - you prove it by your actions.
You are not your OH’s mummy. Nothing less sexy, attractive or worthy of respect than a man baby who doesn’t pull his weight in the household, in the family and with parenting. If your OH ‘doesn’t know how to look after the children’/‘doesn’t understand’ about basic things like food, safety, engaging with his children, ‘can’t cope with them on his own’ or ‘can’t put them to bed’ then he needs to practise, practise, practise until he gets better at it, not be given a get out of jail free card to opt out of the difficult, dreary bits of looking after his children.