Don't break up. Fix the problem. Start the romance again. Go on dates again. Work on winning each other over again. This is why there are so many failed relationships. If you love each other and are best friends then breaking up is not the answer.
unpopular opinion: even tho I don’t wanna get married until later in life, I wouldn’t mind if the next person I dated was the last & we just got to do life together until then. loving 1 person the rest of my life sounds amazing & idk why people are afraid of love & being serious