Don’t doubt the mind fu#k it can be for the mum and be ready to support her fully despite you wondering where the rational women you married had disappeared to. This may not happen, but it might.
Don’t be proud, 2nd hand clothes from friends with slightly older children are a massive pound saver.
Watch them a lot when they sleep, it’s very very therapeutic, and will make you sob like a baby sometimes.
Go on a journey and find a source of energy and harvest it.
Take photographs of you both in the first week, you will laugh hysterically in years to come when you see how sh1t you looked due to tiredness.
Generally try to enjoy the experience and remind yourself how lucky you are every time you yearn for childless times .