Zhè bù diànshìjù de zhǔxiàn shì yí duàn hūnwàiliàn.
The main plot of this TV drama is an extramarital affair.
Tips
usage
婚外恋 and 婚外情 are nearly synonymous. 恋 emphasizes a romantic attachment, while 情 covers both romantic and sexual dimensions. Both are neutral descriptive terms rather than explicit insults.
