About how old are they supposed to be and why i ask

Well, there were never 'specific' ages given, but from the casting sides of the pilot episode, it was said that James and his wife are in their late 30's.

James met Stacey during their freshman year of college, first semester econ class (he said this during the pilot episode). So you can assume that they were both probably 18 years old. They were together for twenty years, but only married for fifteen of them. My best guess is that they'd be about 38 years old.

We were never told if Stacey works of not, since her character is a - from my perspective - a poorly developed plot device, the writers did not pay much attention to the details. She may have worked for several years before having kids, or perhaps she and James had difficulty. Or, another scenario would be perhaps they were 'waiting' till James was more settled in with all things Amerimart (including Katie). It seems that the majority of their marriage was built alongside James' career, so obviously something had to give.

I think these charaters are aged the same as the actors who play them. The actors who play Duncan and Lisbeth are certainly old enough to have a 19 year old child. The actors who play James and his wife are in their late 30's which would allow them to know each other for 20 years - stemming from their college days. Of course, these actors all look incredible for their ages - all of whom, I'd bet have had various types of cosmetic work done. Meow!!!!

Michael Vartan definitely does not look 44.