People often get the misconception that successful blogging is easy, but that's completely untrue. That doesn't stop spouses with Pollyanna eyes trying to start up their own blog and emulate their hubby. Mom bloggers have it a little bit easier as far as support groups, etc., but the competition is fierce.
There are mom bloggers on every topic under the sun and trying to carve out your own niche isn't easy. Dad blogging is much easier because let's face it: we're more laid back. We don't sweat the small stuff and if things don't happen as fast as we want, the we just go with the flow. This is where bringing in the spouse can get a little hairy.
They may want to get as popular or as many hits as you in a short amount of time. They want instant gratification and that's not going to happen. You need to sit down and talk to her about the logistics of blogging and what she needs to do to start her blog and make it successful. The talk alone might be enough to have her reconsider.
You can help her out by promoting her on your own blog and asking other blogging friends to do the same. Just don't fall in the “write this for me,” trap. It's where you're suddenly writing her posts because she doesn't have the time. Once you start, it never stops.
Having two blog writers in the home can be fun, but they both need to know that they are separate and things won't always be in the same ebb and flow.