Dh and I disagreed - he wanted 2, I wanted more.
Our compromise was that I'd get a mirena and once we were sure we were done, he'd get a vasectomy.
I went through awful PND and severe jealousy when one of my friends decided to have No3, but worked through it (with counselling).
I then had some decidedly odd symptoms, was sure I could feel the coil, had a couple of half hearted periods (had nothing since it was put in 6 weeks after ds was born in Feb 2002 - this was March-ish I think. He was just 1 and dd1 spoiler was 3. I saw my GP, was booked for an ultrasound to check it, and we used condoms - was too late. Even before the u/s I was feeling queasy, being sick and incredibly tired. Then I had a really severe symptom I'd had in the previous pregnancy with ds (renal colic and passed a small kidney stone).
The test was +ve! the u/s was rescheduled with the obstetrician rather than the radiologist. I was more shocked than dh!!
Our dc are now 14.6, 12.6 and surprise dd2 is 10.9. We can't imagine life without them all. I was horrendously unwell all through the pregnancy and for 18 months afterwards at least. My kidneys were so badly affected that dh was able to have his vasectomy before dd2 was born, very unusual. Another pg would have cost me my left kidney.
How can I put it? If I was told tomorrow I could go through all the hell of kidney illness, depression, giving up some of our dearest dreams due to the affects on my health and have another baby, I'd say no. If I was told tomorrow my past could be re-jigged so that I was well, but dd2 would never have been born, I would reject that totally. Dh is a fab dad to all 3 dc, dd2 was born just after his Grandma died (3 weeks) and has her name.
This probably isn't helping, and I didn't mean it to be so long. Our #3 was unplanned but it worked out. My dad and mum had their #3 to save their marriage, and it didn't work, and my mother walked out when my db was 4 (leaving me, and my sister and brother).
I'd never suggest you should have more dc than one partner wants. We know we were incredibly lucky that for us, it worked out.