Some ideas could be - she's hiring an escort to keep her company but despite being (unhappily) married she starts to feel more for him. Or she could be the one who's the escort and serving some of the most famous guys in town.
Or her own husband (and his family) want to get rid of her and ship her off to a mental hospital. She's of course more than sane but the places scares her. She meets another patient who sadly has major issues but they fall for each other heavily.
Another idea could be her being a pen pal to a guy in prison. His case was all over the press but she wasn't glamorizing his deeds but saw the person behind it. He asked her to visit him and despite a few doubts she does. What will happen?