You don’t sound mature enough to have one child let alone two.
Demanding you start trying now not because you want another baby, but because you want to get back to work sooner rather than later.
In fact your whole references to children are so emotionally detached that I’m not sure you wanted children at all and have just had them to fulfil some kind of what you think should be the norm, hence why you’re breaking it down as some kind of transactional deal which you feel has now been broken.
A three year gap is not a large age gap. It isn’t. In fact given your current child is 9 months old now, and the average couple takes a year to conceive, you’re not likely to end up with a less than three year gap at this point anyway.
Or you could have secondary infertility.
Or you could miscarry and not have a baby straight away.
Just how long are you prepared to wait to conceive this hypothetical child before you give up? You won’t have longer than six months before the dreaded three year gap kicks in, so clearly you want to go to bed tonight, dtd and be pregnant by morning, otherwise you’d best give up now lest the children are too far apart in age.
TBH I think your DH is right. And if you are insisting on behaving like a petulant brat, then it’s probably best if you don’t have another baby.
Grow up.