Fuck me! This thread us full of outdated misogynistic crap!
Racecar - in particular the idea that only the woman is responsible for providing/paying for childcare! They're his kids too! If op goes back to work (which she is ABSOLUTELY entitled to do) then she is only responsible for half the childcare costs.
Op - you are very vulnerable if dh leaves, becomes sick/disabled, or dies.
The longer you're out of work the harder it is to get back in to it. The harsh truth is most employers don't think particularly well of women who haven't gone back to work once children are primary school age. They question your commitment and think you'll find it a bigger adjustment than for those who haven't had a break or who've had a shorter one.
You'd not be ruining ANYONE's lives! What he means is he's panicking HE will actually have to finally step up and BE a FATHER! He's clearly had it FAR too easy to this point!
If YOU want to you could look into training/extending your education initially but there's absolutely no reason why you can't go back to work. Millions of families have 2 working parents and it works just fine.
Does your husband do any parenting or housework?
In terms of working as a lab tech, remember colleges and uni's also use them. Uni's tend to advertise their jobs on their own sites rather than elsewhere as they tend to try and employ alumni/those already known to the uni (even though that's illegal) so look on college and uni sites for jobs.
But doing your pgce and training as a teacher also an excellent idea - most places are crying out for science teachers!