Romantic False Lead

This is the love interest's love interest; the person brought in, either for an episode or an arc, to date the one that the main character (or just a character) is in love with. The smitten character will be jealous, take an instant dislike to him (often being blind to what attractions he does have), and do whatever they can to sabotage the budding relationship. Usually, the character is either an alpha-dog jerk or a bland, boring milquetoast. They may also be the character's always someone better or "The Ace" to really inspire the Green-Eyed Monster (metaphorical name for the term "envy") to take hold.

This is a hard character to successfully pull off, probably because they usually start out more as a plot device than a character. In many cases they exist solely to create tension and keep the lovers apart, so there's a real risk that your Romantic False Lead, rather than proving a worthy rival to the main character's romantic interests, will simply end up being a rather flat, boring character who just seems to show up and occupy space between the two romantic leads. As a result, this can often risk the show falling into a Romantic Plot Tumor. Furthermore, except in rare cases the False Lead is unlikely to generate the same loyalty or sympathy as the main character, meaning that if your audience is Genre Savvy about what's happening they're likely to just spend the time the False Lead's around loudly wishing for him or her to just go away (and possibly die) already so the two characters they're interested in seeing together can actually get together.

Characterisation can also be tricky. If the false lead is too likable, then the jealous character will seem like a selfish jerk who cares more about winning their beloved for themselves than seeing them happy — or alternatively, since 'perfect' tends to equal 'uninteresting' in the minds of many when it comes to fictional characters, a 'too' perfect and nice character will just lose the audience's interest in comparison to the more flawed and interesting main character. On the other hand, if he's too unlikeable, we will wonder what the love interest could possibly see in them and lose respect for them.

When introduced for a short arc, often exists expressly for the purpose of contrasting their relationship with the Official Couple's, in order to show how perfect the "official couple" is for each other.

Sometimes to up the angst, the writer will go so far as to marry the love interest to the false lead. If this happens, expect the Official Couple to have a tawdry affair.

Occasionally, the writers step in themselves to engage in Cleaning Up Romantic Loose Ends. This is usually another trap in and of itself, as it is difficult to do so and not seem cheap, as happens with Derailing Love Interests.

A subtrope is Disposable Fiancé.

Compare Hopeless Suitor, Romantic Runner-Up, New Old Flame, and Wrong Guy First. Also compare Temporary Love Interest where the relationship is unsuccessful because there is no Official Couple and that won't change. Often the focus of Die for Our Ship.