Anyone who has ever been in love knows that relationships are complicated. Once the initial butterfly phase of the romance is over, it's perfectly normal to fall out of love with your partner or drift apart. People change, couples evolve and you know, sometimes it just doesn't work out. The best thing you can do when that happens is to communicate. Express how you feel with respect and honesty, then negotiate a civilised split or look for solutions together if you both think the relationship can be saved.
But on the flip side of that relationship coin, there's a much less ideal situation: your partner decides to completely hide the fact they're no longer in love, maybe even pretending everything's just fine. Out of cowardice or convenience, they let the relationship slowly die without