@branstonbaby
How depressing that your MIL didn't speak to you for days for having a 4th child. Jeezus fuck! What a vile way to treat your 'family.' Why such negativity?! 
When I was a young lass (mid 1970's,) there were 32 houses in my road, and around 13-14 of them had 4 or more kids One family had 7 kids in a 3 bed house. The 4 girls slept in 2 sets of bunk beds in the biggest bedroom, the 3 lads slept in the middle sized room - (1 set of bunk beds and a single,) and the parents had the 7 x 8 feet boxroom! NINE people in a modest sized council semi! NOW people piss and moan at the council if their kids don't have a bedroom each!
Anyway, I digress. Although over a dozen of the 32 families in my street had 4 or more kids in the 70's, I can count on the fingers of one hand, the amount of families I know with more than 4 kids now. I know FIVE families actually. One is my cousin (5 kids,) one is a friend from school (6 kids,) one is a friend of my daughter (she has 8 siblings,) and another is a friend of my other daughter (she has 6 siblings...) Finally, I know a family in our road (10 houses away - 5 kids.)
And I know just 4 or 5 families with 3 kids. Everyone else I know has one or two. (Or none!) So the odd one having more isn't going to hurt is it?! Especially as many couples only have one now, and some couples have none!
There are 7 cousins in my family (including me,) and we have have 1, 1, 2, 2, 2, 2, and 5 kids. (I have 2.) So between 7 of us, we have 15 kids..... SO 2 kids each on average IYSWIM. My one cousin has 5, but the rest of us 6 cousins have 1 or 2. So it matters not that she has 5.
I contacted a friend I knew from little school last year (on Facebook) a girl called Lynn. And I told her I was married with 2 (grown) girls. I said how many kids have you got? She said 'oh gosh Kim, this is really embarrassing,' and put a blushing smiley. I said 'what is?' She said 'I have 6 children!'
I mean what the fuck? She was apologetic and embarrassed at having 6 children, like she had done something wrong or bad. Upshot was, she had been made to feel a bit shit about it by people, including extended family and so-called friends! She was still with the same man she knew from school, and they both worked, yet people made them feel bad.
I don't recall ANYone being made to feel shit for having 3 or 4 children or more pre 1980's. So I cannot fathom why people having more than 2 children get so much negativity. And I don't buy the 'world population' story, because most people in the UK, only have 1 or 2 children.
SO to @TheLegendOfBeans if you want a third child, then go for it, and fuck the haters!