You’re not failing - you’re doing great - it’s your husband and his Mum failing you.
This is like seeing my first marriage written out - albeit the 80s though nothing like my parents’ way of living so quite a shock.
Don’t let them persuade you that it’s you and feel guilty you’re not some (messed up) version of a stepford wife.
My own marriage just got worse until I ended up in a refuge - mil still blaming the wife - not personal same with her other son.
It’s both your baby, both your home, if you’re not a team then don’t be his slave/ I can tell you now that you will never, ever do enough for him in their eyes, or not as well as she did, or you’ll do it wrong, even if you did become a Stepford wife.
The HV sees this / you could speak to her for advice, referrals or help.
Every single hour this continues is to your detriment and will take you longer to know afterwards what normal is.
Take care of you and baby - let your Mum help you too.