Am I overreacting?

You are definitely not overreacting. Tell your husband to fuck off.
You are the mother, so you decide how long you want to stay at home to raise your child. No nanny can replace the mother. Sorry to say, but he seems to be a total idiot and jerk.
Who is this live in "nanny" supposed to be, working for less than 500 GBP a month?! His secret side chick/ fuck?
We had au pairs (keep in mind: no qualified nannies) and they did cost us 150-200 GBP a week for 45-50 hours weekly, plus food and accommodation. So, he is dreaming if he thinks he can find someone qualified for less than 500 GBP a month for 70 hours a week?!?!
I went back to work after 5.5 months and I can tell you, it was hard... Not just the stress of working full-time and taking care of a baby; no, the worst was the separation from my baby for minimum 9.5 hours a day during the week. It was also hard for my baby not to have me around full-time anymore. I am pregnant again and this time I decided to stay at home for 2 years; not doing the same again

At least in London, live-in nannies still charge you 600-800 GBP a week for 45-50 hours.
My advice: send him to work for 70 hours a week or more; let him run double shifts because I am sure he won't be that useful at home but be a pain in the backside and more stress for you . Shouldn't be a problem for him - if he can expect that from you.

You aren't overreacting. Ur husband is having misconceptions and exceptations way too high. It takes a while to heal from any sort of delivery. He also is missing the fact that newborns need their mother's and he's pushing for something that you don't even want to happen. This is inconsiderate of ur feelings and expects you to do things way before you may be able to. You should be able to raise ur child ur way not how he wants things to be done. Since this is ur first, im guessing he doesn't understand any of this.

Your husband is an idiot. You're not overreacting at all. The cost it would be to have a live-in nanny, it would barely cover most wages nowadays. Cut back on some things and live within your means so you can stay home with your baby. That's where you want to be and if he tries to take that away from you you'll never forgive him xx

I no longer live in the UK, and I live in a part of the world where live in nannies cost $400 per month. This amount is sooo affordable for us, but even then I refuse to hire one. You may have other chances at experiencing motherhood but your child only gets once chance of being one and there’s NOTHING a child needs more than a mother. Their OWN mother. Money comes and goes, these things won’t

You’re not overreacting, I would never trust a stranger to care for my babies, and mothers care is very important in the first three years nothing can replace it.

Your husband is treating you like you are a soldier who needs to go back to war lmao ,he can get a side hustle.
Were there any discussions prior to giving birth about raising the baby?

Leave him x

What a tool. He doesn’t even understand what he’s trying to ask for and why it’ll never work. Or seem to care how it will effect you *facepalm*

Girl men always try to take control and lead but the truth is that women lead during the first years specially during pregnancy and 2 years postpartum so make sure u get ur experience just how u want it . This is a once in a life experience

Yeah, no. What do YOU want?