Married People who can't have lunch with a friend

[Osito]

They're not a friend if they can't make the time for you once in a blue moon.

[BriteSpot]

this is very common, unfortunately, with immature, co-dependent
women that are newly married or playing house.
i say, leave her lone for a while....the minute he disappoints her she'll
not only wanna have lunch/dinner, she'll be willing to pay for it.
get ready, she will ONLY be discussing him.

[JanND]

You mention a Saturday or Sunday....Maybe she could take lunch during a workday.
Weekends are sometimes sacred for folks that work all week.
Also, you don't determine whether your friendship is important based on her not being able to go to lunch on a weekend. If that's all it takes for you to decide she isn't friend worthy it may not be worth sacrificing a weekend day for either of you. Her spouse may be her best friend.
Invite her on another day/time.