Brother? I Don't Have a Brother

A couple of nights ago my dear son and I were eating dinner together. My dear husband was working late so it was just the two of us. We were quietly eating for a couple of moments and then my dear son initiated this conversation:

L: My friend T is a brother.
Me: Yes, he is.
L: Brother? I don't have a brother.
Me: You're right.
L: That's okay that I don't have a brother. I don't need one.

I was so stunned by this conversation. My dear husband and I have never said anything to L about wanting another baby or him having a sibling some day or our IF. NEVER. I admit that I have purposely not brought it up because I don't want him asking me for a sibling when we have struggled so much with our infertility. I mean, how do you explain to a child of his age that you REALLY want another child, but that you have not been able to have another one. You know, good ol' Dr Phil says that you should not involve children in grown-up problems, so I guess that I have never felt that it is appropriate to discuss with my dear son. Each day I wake up and try to enjoy him to the fullest because I don't know if I will have the opportunity to have another Angel.

So, if my dear son doesn't not care about having a sibling, then why do I care about having another child so much?

(okay, I have a million answers for that question, but I just wish that I could have his attitude, just for a day.)