I'll start.
We always wanted 4, and reasonably close together. DH's siblings are 4 and 8 years younger than him. That's a whole generation and he wanted nothing like that for his kids.
We started trying when Darcy was 6 months old...it took 2 years. When I did fall, I lost that bub at 12 weeks. I fell straight away and now have Nate.
When it took so long and Darcy got older, like you i questioned whether I could have the same feelings for another child, would I cope etc....don't worry, I think everyone feels like that.
Then i did fall, and all of a sudden I was worrying I was doing the wrong thing..then that baby passed away and I decided we were never having another because I couldn't do that heartache again.
Now Nate is here....well, I don't think it's even possible to describe, but I think the love just doubles, it doesn't halve or get split.
i can't have any more children due to some complications i had with Nate, and the day they told me that....there was the heartache all over again.
Georgia won't remember that she wasn't on her own. Heck Darcy doesn't and she's three. She won't remember that she didn't have to share, and she certainly won't hold it against you.
When she learns to talk and she says, "Mum, I love x so so much" you'll forget you even worried....I know I did.