No it’s not.
I presume you expected your husband to be present in the children’s upbringing? I’m sure you would have been quick to criticise if he’d not wanted to look after two under two that you’d decided to have?
Having a baby is a joint decision. Whether you give birth to them is irrelevant other than when deciding on whether you want them at all.
It makes sense if you e.g. want a greater age gap, but nobody should get to say “I want a baby now and given I will be giving birth to it then you will give me what I want.” Life doesn’t work like that. And if that’s how people operate in their marriages then you have to question whether that marriage is healthy enough to bring another baby into.
the OP’s me me me me me attitude will get her nowhere.
She is setting herself up for disappointment, if she doesn’t get pregnant, if she ends up with twins (yes, this can happen), who are close to one another and want nothing to do with their older sibling, if the siblings grow up hating each other, if the second baby has significant disabilities meaning they and their sibling won’t ever have that kind of relationship and they’ll need life-long care.
OP’s rigid thinking is only ever likely to end in disappointment.
Babies are human beings in their own right, and fertility is a dice roll. You don’t get to decide when you’ll have another baby, you can start to try but you can’t decide when the baby will arrive.
And you don’t get to be the one who creates the relationship between siblings. They’ll do that for themselves, and it’s not something you will ever be able to control.