Hi there!
Me n hubby have decided to stop at 3 for a few reasons, and I suppose some a selfish ones....the main one, we want to do things we've never done before and wouldn't do with young children. Like a long-haul holiday (ok, I want to relax on a golden beach while the kids are all old enough to swim safely lol) which I wouldn't do with young chn let alone babies!
And then there's the car situation, (we currently are selling our 7 seater to save money by having no finance), house situation (have a 5/6 bedder but are selling to downsize to 4 bed!) and work, ie money! I don't think we could afford another child as we don't get child tax credits now, so won't in the future either.
On the other hand, children are ace. They give you much more than money can ever give! I get quite sad thinking I'll never feel a baby kick for the first time again, or see them for the very first time...in fact although every new milestone for Gracie (14mth) is a joy, it's also quite upsetting thinking I'll never see another of my children do that again.
I think no matter what ppl say, you'll know deep down in your own mind what you want to do, and as the thought is already there....why not do it?! Good luck with whatever you decide!