I am happy with my decision to stick with one dd. I was 40 when I had my dd, had a rough old pregnancy and subsequent 3 years with a few problems - but all is happy & dandy now.
I didn't feel I could physically cope with another baby and I was worried what impact that would have on my dd & dh.
The guilt was all consuming and I still wonder sometimes what another child would have looked like, would it have been a girl or boy, would it look more like me? etc.
Occasionally I have to take stock and remind myself to enjoy the here and now, to concentrate on what I have got and not what I might have had.
We have a very close knit family and my dd has two girl cousins and two boy cousins who all adore each other. So, in my case, I felt happier in the knowledge that my dd will have a support network as she gets older.
Nobody can make this decision for you but there are good & not so good reasons for having just one, two, three, or four + children.
It's a very personal decision. It took me 9 months to decide in my case and it was a very difficult time as I swayed from one decision to another.
However, we have a very happy family life, full of fun & laughter. I am very mindful of the fact that dd is an 'only' and we don't have any sharing issues with friends or spoilt tantrums as some people associate with an only child.
I've heard people say 'Oh he/ she is behaving like that because they are an only child'.
Ignore the pressure of people asking when the next one is coming along. It's very difficult but i got it off to a tee in the end by just saying 'No' ... it threw people and they never mentioned it again.