When I was in my 20's I received the best advice of my life, from a co-worker that was getting married (I didn't get married until my 30's):
If you want to stay home while children are young, don't ever depend on two salaries starting from engagement on, if you both agree.
Personally, I told dh from the minute we started thinking about kids (we were engaged, not married yet) that if he wanted me to go back to work while they were young, that I wasn't interested in having them. I wanted to give him plenty of time to think about marrying me with this stipulation. Of course, if he lost his job, etc. I'd pitch in (this actually happened and I did go out on job interviews whilst dc was a baby).
Dh whole heartedly agreed, we were both brought up that way, and we both made good wages but him more so, and he told me he would fully support the idea of me staying home. From that second on, everything I made went into the bank (I moved back home with my mum to do this) and for a year and a half saved every penny for when/if we had a baby.
I know this is after the fact for you, but it worked out great for us. Dh and I both had good jobs, we could have lived a very different lifestyle but we live modestly and are so happy that we did what my old co-worker suggested. It is so easy to start off with less and continue with less, than start off with 'more' and go 'down'!