We had decided at the end of last year that we were going to stick with 2 children. (i wanted a third but DH spelled out lots of reasons to not and I agreed at that stage, and so went on with life thinking we had completed our family) A couple of months ago, DH started talking about having a third, so here we are. It is a little daunting, as there could be at least a 4 year age gap between a baby and my youngest. In my favour is that both my girls will be in Prep and Kindy next year.
I guess also, I think of how difficult it may be while they are young, but a friend always tells me to imagine family gatherings as the children get older. The more the merrier.
I hope you can both agree on an outcome - one that makes you both happy.