I found being a SAHM while on mat leave incredibly boring as much as I adore DS.
Now I work part-time because I want to, not because I have to financially. I love it! Don't feel guilty about it although I do love going to get DS from daycare at the end of the day.
I also think that having enough money to be able to provide yours kids with things like good education and travel opportunities, etc actually IS more important than having his mum around 24/7.