I think the first two posters must have really easy kids. I didn't find the transition to three that difficult, but having three is a whole different ball of wax than having two. Our youngest is nearly four, and things are MUCH easier the older he gets. Yeah, I know there will be a lot of logistics as they get older, but that's manageable.
A few things helped us get through the first few years with three (my older ones were 4.5 and 2.5 when baby was born) :
-Containment when you're out. Playgrounds with fences, smaller indoor spaces, that kind of thing. Don't take them all to Udvar-Hazy or something. Start small
-Involving the older two in helping as much as possible, and then praise them out the wazoo when they do
-Acknowledge the change and don't BS them into thinking it's NBD. Of course it is. It's manageable, sure, but it's also another person in their lives, and that is a big deal
-Set aside time for the older two, together and individually. Keep that up.
Good luck and enjoy! I *love* having three, even though I find it much harder than having two. The payoff is so incredibly worth it.
