i have the exact thought as you!!
i used to think that i must hav 2 kids! even after dear son was born, i thought of giving him a lil sis/bro when he turns 2-4 yrs old, depends onour finance..
but everytim ei think of this issue, i ask myself, even if financially we can afford 1 more, or even 2 more kids, do i really want? cos i love dear son too much that i dont think i can love #2 (if i hav) equally..
but my friend whose #2 is around same age as dear son, her elder kid is 5yo, she said she used to wry about this issue too, but she said after #2 is born, all these are no longer any pro alrdy..