Ecchi is usually a genre that's matched with seinen or shonen technically as they're filled with fan services of female characters being exposed to all sorts of vulnerable situations or suggestive things. However, this one, I might call this a female oriented version of ecchi. Feel free to correct me as I have only read a few chapters here and there since I'm marinating this.
I love red flags. Maybe black flag in this case? Though, I don't like how it was implied that her ex husband might have cheated on her.