Bella and Edward were the OTP (one true pairing) right from the very start. As a matter of fact, when Jacob was first introduced in Twilight, Stephenie Meyer hadn’t made any decisions yet for him to be Bella’s romantic partner. Given these two things, I always felt the love triangle was unnecessary and complicated things too much. The love square (or whatever you want to call it) in The Host was probably done better in spite of the fact that it was written not long after Eclipse.
However, an alternative way to do the love triangle is to have Jacob imprint on Bella as a wolf and try to claim her as his mate but ultimately fails as Edward had already claimed Bella as his mate by that time. The imprinting bond could disappear because Bella is already a vampire’s mate or it could linger, in which case Jacob would be simply a friend/brother instead of a lover. If the former occurs, Jacob is then free to be with someone else (like Lizzie or Leah) and hopefully be able to move on. If the latter occurs, Jacob would remain tied to Bella but there’d be no romantic love to complicate things between them.
Of course, Bella and Jacob could just remain friends and their relationship never progresses into a romance, thus the love triangle never comes to be in the first place. A far simpler solution.
If anyone has some other idea, I’m all ears.