What made you decide having X number of children?

My hubby and I were talking, and we were pondering over how many children we wish to have. Either 2 or 3.

Obviously, we took into account everything. Health, money, house, car, trips etc etc.

We really wish to have 3, but not sure if 2 is the ideal number.

How did you decide to have X amount of children? How did you say okay, this is the last one?

I hope I'm explaining myself well, English is not my frist language and I do not wish to be insensitive.