You mean Nienor.It's also the worst thing in the book. Worse than Maedhros hanging by his wrist (worse than the moment where they realize they need to cut his hand off). Worse than the Narn (worse than the moment Morwen jumps).
The reaction of the other Elves.... "Well, you oughtn't to have done what you did, but since you did, I guess you own her forever. Certainly nobody else would ever have anything to do with her, even if she were extricated from the situation, as we all universally practice the virtue of uncompromising monogamy!"