Love triangles can be a big draw for a show, with fan engagement rising in a competition perpetuated by the idea that the winner takes all. Which is why it is very easy for a love triangle to turn into a harmful plot that takes over a show, or that creates a disservice for at least one of the people involved.
Successful and love triangles isn't something you would expect to see in a sentence together, but they do really exist!
If the people in the triangle are three-dimensional individuals with stories that define them outside of the romance, and if the love triangle doesn't overpower the actual plot of the show, there is a chance to really tell a story.
Here is a slideshow that offers some possible examples of love triangles that didn't ruin the content of the show, or the characters involved in it.
Clarke/Raven/Finn - The 100
There is nothing that comes close to Clarke and Raven choosing each other over Finn. This set a tone for the way that women would be treated on The 100, not as love interests but as the heroes of the show that form genuine friendships with one another. It also didn't cause the story to revolve around the lead white guy or the love triangle that he created when he appeared.
(But also RIP Finn Collins?)
Zoe/Wade/Joel - Hart of Dixie
Joel was a refreshing character because he wasn't written as a new obstacle, he formed a connection with Wade as well, and this wasn't a competition. Wade grew as a person in his own relationship and Zoe was happy for some time with Joel.
Kala/Wolfgang/Rajan - Sense8
Why choose? This was such a perfect approach to a love triangle, with Sense8 submerging their characters in true happiness. Kala didn't have to pick one person and lose what she had with the other, and on top of that Wolfgang and Rajan formed a bond of their own.
Elena/Stefan/Damon - The Vampire Diaries
This may be a shocking choice, but hear me out first! It could be argued that the whole Delena vs. Stelena campaign that ran for almost as long as the show was on the air perpetuated the idea that The Vampire Diaries was nothing but one big love triangle. While Elena did have feelings for both brothers, there were plenty of storylines that were at the center of the show. The romance was important, and yet that wasn't all that the show ended up being. Plus there is definitely a case to be made about how the love triangle would be interpreted if social media, interviews, and polls didn't get in the way.
Liza/Josh/Charles - Younger
Whether you are Team Josh or Team Charles, you can't deny that Younger knows what it is doing when it comes to love triangles. There is a way to make both relationships worth rooting for, with a focus on happiness above all else. It isn't for the drama, it is an honest look into conflicted feelings.
Jane/Michael/Rafael - Jane the Virgin
Jane the Virgin did and continues to do an excellent job allowing all the characters in a love triangle to be fully formed people that have value beyond the romantic relationships they may be in. Michael and Rafael may have both been interested in Jane, who wouldn't be. But they had their own journeys as well, with Jane's feelings always taken into consideration but not allowing the love triangle to reflect badly on either of them.