Another option would be to rescue an adult dog. The usually come already potty trained, don't have as much energy, and generally require less work than a little puppy. Granted...you don't get puppy breath and some of the other puppy things that are fun, but I'm a big fan of rescuing animals, and since everyone wants puppies, the adult dogs get forgotten. That might be a good option. As for the timing...well, there's not such thing as perfect timing, right? I have a friend who got pregnant right around the same time she got her puppy. It can be a lot to handle, but at the same time, as a dog owner, it's also so rewarding. And I'm really looking forward to seeing the bond develop between my dog and the baby. Many dogs have a sixth sense about kids and babies...it's true that some get jealous, but more often than not, I've seen the dog take on a protective role over the child...
I think if you and your SO decide it's time for a dog, then you should go for it. Just make sure you are prepared for the extra work and time commitment it will require. And do the research to try to find a dog that fits well into your lifestyle. I don't think you'll regret it!