I don't think one can really 'blanket' what is good for all relationships. When my husband and I first got married, we were both working. We were mutually miserable. He asked me to quit(he liked his job, I didn't). He said he didn't really want me to get another job. I thought that was fantastic, because I didn't really want to get another job. I liked the domestic work(except the dishes). I liked not having to shuffle to find childcare. So did he. It was a win win for both of us.
We can still talk. He tells me all about how his coworkers are idiots. I tell him about all the crap the kids did while he was gone. We can understand without having to directly experience it.
I think its best just to let the individuals in the relationship hash out what does(or doesn't) work for them.
He likes to mow the lawn. I like to cook. It works.
Yes, I was a stay-at-home mom for my kids when they were little too, so I understand the importance of being there for kids, and what an amazing experience that is for those who are able. That said, knowing now what I wished I had known then, I would have worked while they were young. My marriage survived, many do not. The reality is 50-60% of marriages end in divorce, and the #1 reason for divorces are Managing Finances.
Pros to staying at home:
stay-at-home parent has lots of time to bond with children,
less stressful for stay-at-home parent
Cons to having one person stay at home, and the other work:
Financial stress, reduced household income (#1 reason for divorce, financial stress)
Working parent is not able to spend as much time with children, and can feel un-loved and left-out. (Kids typically gravitate to the stay-at-home parent)
Stay-at-home parent is a dependent. They do not own house, cloths, or anything. They are like a child depending on another for support. This leads to unequal views, typically working parent is the "head" of the household, and all dependents are treated as dependents, without as much say.
Stay-at-home parent gets behind on their career advancement, typically will never make as much or climb as high on career ladders as those have spent more time developing their career.
In many cases, stay-at-home parent may stay in an abusive relationship because they are dependent on their spouse, unable to support themselves and their children.
Many children are not as independent or socially intelligent without as much day-care interaction with other kids.
Many stay-at-home parents lives revolve around kids in unhealthy extremes, where child has quite a lot of pressure to live up to stay-at-home parents expectations.
My mom worked, and her mom worked too. My dad's mom was a single mom who worked. It was a relief to me when my mom went to work, as that meant she defined herself as something other than "mom" - so I could be my own person too, rather than just living up to filling someone else's dreams. My mom had an amazing career, and I am so proud of her and the work she did. My kids are proud of me and my career as well - I am able to bring them to work every now and then, and have extra resources for them from my work. My relationship with spouse has drastically improved now that I am working as we are no longer living parallel lives - we can talk about work, we are not stressed out financially, there is no "head of the household" - we are both independent adults who do not leach off one another. We take turns or cook together, clean together, grocery shop together - we do so many more things together. The kids view us equally, no longer just come to "mom" for help, they come to both of us.
There are many different family situations, and everyone finds a way for many different things to work. Just words of warning from the 50-60% of people who end up getting divorced, if you are a sty-at-home parent, be very careful of any $ that is not yours you are spending... be very careful that working parent feels appreciated for what they do, and take job of cleaning house/cooking/exercise seriously as you will be resented if you are sitting around on couch all day, you will be resented and not respected if you are not working as hard as they are.... Keep yourself educated, spend time getting a degree or something so that you are able to return to the workforce if needed (car accident, to just kids getting older).
Best wishes to everyone out there - it is difficult to make families work, but worth it. Our relationships, for most, are the most precious things we have.