I have had a great deal of time for thought lately, and my mind always ventures back to those times when I made my most difficult decisions, and when I gave my hardest counsel. Aikanáro's decision not to wed Andreth was, of course, his own. I would never have forbid the union, no matter how little I disagreed with it. I was his brother, not his father, nor hers. But despite the sadness it caused both of them, I do not think I would have counseled either of them differently. Their pain would have been intensely worse had a marriage between them been allowed.
It was a time of war, even if we had been in a Watchful peace for some time, and our kind does not marry in times of war. With Aikanáro being the warrior that he was, this was even more crucial.
Secondly, though I do not doubt their love, I truly believe that marriages between the Eldar and the human race must be only allowed for reasons of the Highest Doom. They are not something to be entered into lightly, or without great thought.
Thirdly, Aikanáro's pain would certainly have been worse when she ultimately died after so short a time had he allowed himself to love her from anything other than afar.