* Future wife wanted to marry Bernstein, knowing he is gay
* Mentor Copland says some Bernstein letters "fit for flames"
* Desertion of wife dying of cancer was low point -editor
By Michael Roddy
LONDON, April 11 (Reuters) - It may be one of the saddest but most loving letters written by a woman to a man - Chilean actress Felicia Montealegre telling her future husband, conductor and composer Leonard Bernstein, she knows he is homosexual but wants to marry him anyway.
The letter, in which Montealegre says "you are a homosexual and you may never change", is among hundreds in a recent volume "The Letters of Leonard Bernstein" edited by English music scholar Nigel Simeone, who previously wrote a book about Bernstein's famed Broadway musical "West Side Story".
For the volume of letters, 650 of them in a book of almost that many pages, Simeone said he had sifted through some 10,000 in the U.S. Library of Congress written by the prolific Bernstein, with missives dating from his youth until his death in October 1990, and from his correspondents.
"I made three piles and then went through the pile of 'must haves' and cut it by about half," Simeone told Reuters. "I ended up with what I thought had something to say about him, about his music or his career or his family that were of interest."
The resulting volume contains letters to and from many of the big names in music of the past century, including the composer Aaron Copland, who was an early influence, conductor Serge Koussevitsky, who helped give him a start as a conductor, and the composer David Diamond, who was a close friend.
Other musical names range from soprano Maria Callas, who spotted Bernstein early on as a huge talent and got him to conduct for her at La Scala opera house in Milan, to Pierre Boulez, Nadia Boulanger, Charles Munch and Dmitri Mitropolous.
A lot of these will be mostly of interest to the music world, but some are particularly touching, like the ones from Montealegre, or cast a new light on historical events.
Among the latter is one from U.S. President John F. Kennedy's widow Jacqueline, writing in 1968 after Bernstein had arranged a memorial concert for JFK's assassinated brother Robert. It starts out: "It's 4:00 in the morning - after this long, long day".
It goes on to thank him for cutting through the church bureaucracy to arrange to have Mahler and Verdi played at Robert Kennedy's memorial Mass.
"I thought it the most beautiful music I had ever heard," Jacqueline Kennedy writes. "I am so glad I didn't know it - it was this strange music of all the gods who were crying."
Simeone said he had been thrilled when Caroline Kennedy, the daughter of JFK and Jackie, consented to let him use it.
"People said to me it's great but there's no chance in hell you'll get to use it. I must have caught her on a good day because I couldn't have had a nicer reply from Caroline saying, 'What a lovely letter, of course you can use it'."
One of Bernstein's most revealing pieces of correspondence is with Copland, the creator of the sound of the American west in his ballets "Rodeo" and "Billy the Kid", to whom the younger man in 1940 aired his frustrations, asking: "Why practice Chopin mazurkas? Why practice even the Copland variations?"
To which Copland sagely replied: "What terrifying letters you write: fit for the flames is what they are. Just imagine how much you would have to pay to retrieve such a letter 40 years from now when you are conductor of the (New York) Philharmonic" - which Bernstein was to become 18 years later.
The letter from Montealegre, written, the book says, either in late 1951 or early 1952, must rank though as one of the most thoughtful and touching "prenuptial agreements" on record:
"First: We are not committed to a life sentence - nothing is really irrevocable, not even marriage (though I used to think so)," Montealegre wrote.
"Second: you are a homosexual and may never change - you don't admit to the possibility of a double life, but if your peace of mind, your health, your whole nervous system depend on a certain sexual pattern, what can you do?
"Third: I am willing to accept you as you are, without being a martyr or sacrificing myself on the L.B. altar. (I happen to love you very much - this may be a disease and if it is what better cure?)"
Despite her having gone with eyes wide open into a marriage that produced two children and which later letters show was immensely fulfilling and exciting, Montealegre could never have predicted the terrible comeuppance she got when she developed cancer and Bernstein abandoned her for a male lover.
Although the couple were reconciled shortly before Felicia's death in 1978, Simeone sees it as a low point in Bernstein's otherwise distinguished career and inspiring life.
"There's no getting around it, that is not an edifying episode in Lenny's life," Simeone said.
"At least he had sense when people said, 'For Christ's sake, sort it out', he had the sense to go crawling back to Felicia.
"It was absolutely the low point. It was horrible." (Editing by Mark Heinrich)