I wouldn't say this topic is super controversial. The book Notes on a Scandal is far more extreme, where the female teacher is in her forties and sleeps with a fifteen-year-old student. No topic is above exploring in my opinion. I would only worry about making it believable/real/authentic, and writing it well. Make sure the reader believes it would happen. That your character's motives ring true. That we're with them as they go through it. It will be pretty easy to make them likeable if they're rounded and real people who are simply flawed, and make a mistake.