If someone asks whether Joe marries Esmeralda of his own free will, you don't understand that? I would understand that as asking whether Joe was forced to marry Esmeralda. That is, something like, was Esmeralda pregnant, and was her father threatening Joe with a shotgun?
Of course I understand situations like this just fine, it's later in the conversation that people stop making sense.
Joe chooses to marry her because he wants to. Free will everyone's book.
Joe chooses to marry Esmeralda instead of being shot. Still free will in my book. Joe chooses between things he does not want, by choosing the better of two options (from his own subjective opinion.) I can see though why some would disagree with this, death is not considered a "reasonable" choice. We all make choices like this all the time though. Albeit less dramatic ones. The thing is that obviously isn't what folks have been arguing about for the last 2000 years.
(Note the scenario you offer is also not pure because for most of us there is strong moralistic emotion involved with children. Moral and social obligation is another discussion entirely.)
Free will in the philosophical lore doesn't seem to be predicated on choice as such, but something else. What exactly I'm not sure, I feel like I must misunderstand as the claims made are nonsensical to me. It doesn't help that people are vague about it.
Usually it's phrased as in opposition to determinism, that is "that every effect has a cause." What I don't get, I guess, is what exactly a "choice with no cause or context" could possibly mean.
Even whimsy is about pleasure (value judgment, as in assessments about relative preference.)
I used to think people meant that our choices have an effect on our future, something I agree with by the way, however this is only true because of determinism.