Okay, "woman divorces her husband" doesn't seem like a big enough issue to pin a whole movie around to me - but would I be correct in guessing that TX comes from a country or culture where it *is* a big deal for a woman to initiate divorce and take the kids?
If so, TX, you have two options. Setting this story in a culture or country where divorce is less easy or common, and where there's an assumption the man gets the best deal out of it even if he was in the wrong, will give your story strong stakes immediately.
Or: if this is going to happen in US/Europe/ other culture where divorce is less of a big deal, you need to raise the stakes dramatically. She starts the divorce and takes the kids, BUT her husband kidnaps the kids/tries to kill her/frames her and her sent to jail... Something.