The impossible decision - a 3rd child?

In your situation I would enjoy the two I have and look at going back to work.
I have four and rearing children has been a long slog, they need you for much longer now.

If in doubt, don’t. You’ve given lots of good reasons NOT to have a third and only one reason TO - which is you have a hormonal urge. Not a good enough reason to outweigh all the cons IMO.

Ask yourself what happens if you had the third and then still wanted another? And another?

@ForPeachBee How old are you currently?

It’s possible you will cope fine but also consider your third could be twins. Yes you will have your large family but it could be restrictive to your existing children.

Go for it. You can afford to and the kids are older and at school.
Ignore all the negativity.

@ForPeachBee The only thing I would say is have you considered how it will be in peri? I started feeling peri at 42 so say in another 10 years time your kids will be 17, 15 and 9/10. That's a lot.
I had my last at 39 - two other kids with my ex-husband but they only lived with me 50/50. My three are now 19, 16 and 6. The older two are self-sufficient, eldest at uni, but the little one is, well, little! I work a demanding job and now 45 when perimenopause is is full-swing and it's something I'd never considered!
However, I think you said you're a SAHM so it might be easier for you?
Having said that, being a SAHM would my idea of a complete nightmare!!
I have no regrets about making my now husband a dad and our LO is definitely his first and last. He is incredibly present; we share childcare and housework equally. And my older two being with their dad half of the time meant we could give lots of attention to our baby/toddler when they were away, whilst ensuring we made time for them when they came home.
Would I have had a third under different circumstances? I don't think so. Ages of around 9, 7 and newborn full-time will be incredibly hard. Then there's peri/meno on top in about a decade. How involved is dad?

If you feel your circumstances are right I say go for it. I had my third at 37 when my older two were 5 and 3. Id always had it in my head I wanted three but I still had a wobble about whether it was right for us or not. In the end it was something I read on here that swayed me, something like you could end up regretting not having a third but you would never regret having that third baby when they are here. And its true, I would have regretted not having her. She's completed our family and after her I knew I was done. I love having three, its crazy but so much fun.

Your age is in your favour, I don’t think the gap is crazy big, sounds like money would be ok. Like you say, older ones will be at school so you’d get lots of time with baby and to try and keep on top of things.

The bit that gives more pause is your children’s SEND and what the details of that - will you be able to be as available to them as they need, would they cope with the challenges of a baby/toddler in their space.

I think just talk to your DH. He will perhaps see it a bit more objectively than you and hopefully you can work it out together.

And, most importantly, your DH needs to want a third child too.

We agonised but decided not to as SEND journey here too and we were concerned about having a third dc with really significant needs. Ten years on when we chat about it DP and I say thank god we didn’t have another one.

Nobody can make this decision. Only you and your partner. I think affordability is a big factor these days. Size of your house. Your jobs.