I have two children 3 years apart. They are sort of close as adults but would do anything for the other. Then I have a child who is 7 years younger. He is almost grown up. I worried very much about exactly what we you are worried about. So I planned on getting him a dog when he was 10 so he wouldn't feel so lonely when both brothers were gone to college. So we did.

But the thing you have to remember is that even though he might feel like an only child at times, he's not. You must work hard to make sure they have some shared memories that they can all laugh later about it. Have them all camp out in the back yard when they're older. Take lots of movies. Make them do the dishes together. That's one of my kids favorite memories. Go figure.

And if you're the only one of your friends with a young child, don't ever let him feel like an afterthought. New years Eve was always at my house so the youngest could have a buddy sleep over. I didn't go out for NYE for many years, but we had a few friends over and they had kids champagne at midnight. Nbd. Make sure he's not being dragged along where's there's no other kids because you couldn't find a sitter, and make sure you don't have a sitter every weekend.