i think whether you are an only child or if you have a load of siblings, everyone has the grass is greener moments, i guess its human nature,
my dh is the youngest of a huge family, mostly scattered to the 4 corners of the uk, he sees maybe one or 2 of them a few times a year, none of them were ever very close,
me, i am the middle one of 3, younger sis, older bro, but for most of my life wished dearly i was an only child, never more so during my mum's illness, death and the aftermarth, they both managed to make what was a difficult time a hundred times worse, i don't speak to my sis unless i really have to, i can't be bothered with the competing she goes in for, nor her nasty bullying, as for my bro, i can tolarate him, but he is far more intrested in my sis because he feels she is more useful to him.
luckily i have been blessed with several wonderful friends who i feel are far more like my sisters than my own siblings ever were.
for the record, dd is an only, and to be honest, would not have had the wonderful things we have been able to give her had she been one of several, i think she is happy as she is, she is an independent, outgoing young woman with a very happy circle of good frineds.