I would look at your bandwidth long term, you will need to keep working, presumably full time, how do you find this at the moment with one child, do you think you will cope with 2? what happens if either your child or your husband needs more care, will you be able to manage this whilst working? Can you afford to be part time if it gets too much for you? If you did split with your husband, could you manage on your own with 2 kids?
Would you be happy living in your current flat with 2 children - is there space for you for at least a few years? Will your husband need adaptations to the flat? If you moved, how much would it cost? What would your commute be? Would this be sustainable long term?
Is your husband as keen to have a second child as you?
if it was me, I’d probably reorganise things a bit, if your husband is only doing very part time sporadic work, you would be better him being a full time SAHD and you focussing on your career, he could sort all childcare, food shop and life admin to take the pressure off you. I guess if you are earning 6 figures you don’t get the free childcare. Would he be willing to stop working and be a SAHD? If you did this, you’d need to be a proper partnership with no resentment on either side, my FIL was a SAHD and it worked well for them (although very unusual in 80s/90s).
DH and I are going through a similar debate, ours is around whether we can we cope with a second mentally, our son is full on energy and a very poor sleeper. DH doesn’t want a second but I would, although I don’t want to force him to have a child he doesn’t want - I think that would be worse for the whole family.