If the course of true love never runs smooth, it bounces like a buck-board on daytime television.

The latest from NBC's "Days of Our Lives" is that the chaste, year-long engagement of David, Banning and Valerie Grant, soapdom's only interracial couple, is Kaput. According to the script, the reason for the rift is David's infidelity. But according to the actors portraying the color-crossed lovers, the reason is racism, real-life racism.

"They're breaking us up because the story line is unpopular," said Richard Guthrie, who plays David. "The studio has been getting a lot of hate mail from people a lot threatening to stop watching the show."

"When they get enough of those letters they respond," said Tina Andrews, the black actress who appears as Valerie. "One letter said, 'I hope you're not going to let that nigger marry that white boy.' Apparently they are not. I'm being canned."

Andrews pointed out that her television mother and father played by Ketty Lester and Lawrence Cooke, already have been "written out" of the script. With both the black story line and the interracial romance eliminated, she said, Valerie is expendable.

Spokesmen for NBC in Burbank and the show's coexecutive producer, Wes Kenny, confirmed the couple's imminent breakup but denied the split was a reaction to unfavorable mail.

Speaking for Corday Productions, the company that wons the show, Kenny said that although mail is read, analyzed, studied for trends in viewer response and discussed with the show's writers, public reaction has not affected the long-term plans for the romance.

"This breakup has been planned from the very begining," he said. "There has been no change of direction."

Though the Neilsen ratings are considered the primary arbiter of how well of poorly a program is doing, viewer mail can be used to pinpoint potential bright of trouble spots in the story line. A drop in the ratings backed up by a negative viewer response to a particular subplot will more than likely result in the subplot being quickly amended or eliminated altogether.

Kenney said that while "Days" ratings hs fallen in the last year (from its perennial position in the top three to a current No. 7 in a field of 14), the mail reflects a 550 split on the subject of David and Valerie.

Guthrie said his personal mail ran 50-50 during the "just friends" stage but grew increasingly negative as the relationship warmed up. Currently, he said his fans are 70 per cent opposed to the romance continuing.

The subplot surrounding the David-Valerie split is complex, convoluted and goes like this:

After a fight with Val about her mother's opposition to the marriage, David finds himself jilted and at loose ends in th apartment of his good friend, Trish. Long distrubed by her mother's seamy past (a prositution bust years before) and ridden with misplaced guilt because her drunken impotent stepfather looked at her funny when she was a child, Trish confesses her resultant viginity to David. Deeply touched, he offers to teach her everything she always wanted to know but was too hung up to try. Trish agrees, reluctantly. David and Val make up and wedding plans go forward. Val receives a medical scholarship to Howard University in Washington, and the couple journey to the capital where they find a nice apartment and a job for David. Trish recovers from a bout of multiple personalities after killing her stepfather with a steam from only to discover David has taught her how to be pregnant, too. The truth comes out. David decides to do the right thing and give the child a name, while Valerie goes off alone to study medicine, a virgin to the end."

"There's logic to the whole thing," said producer Kenney.

The logic, according to Andrews, is the Salem (the fictional small town of the show) loses its last black character, daytime TV loses its only major black story line and interracial romance and she loses her job.

But the loss of a meaty role is not what's bothering the actress. With credits that include the role of Aurelia, young Kunte Kinte's girlfriend in "Roots," and a costarring role with LeVar Burton in an upcoming NBC-TV movie, "Billie," she says she doesn't need the soap finiancially. Her main complaint is the way David and Valeris's story has been presented. What others have called a "delicate and tasteful" handling of the romance, she calls racism, written into the sript and practiced on the set.

One feels silly asking the question of another adult: "Why can't David kiss Valerie?" But six months after the couple became engaged, Andrews asked that question of one of the show's writers.

"I was told it was some kind of policy," she said. "I went home that night and thought to myself, "Kissing can't be the problem - all other couples in love on the show kiss. And the David had kissed other females characters. What's wrong with Valerie that would cause such a policy to be put into effect?"

"The problem is that Valerie is black," she said. "Well so is Tina Andrews, black all the time, on screen and off. When you say David can't kiss Valerie because she's black, you're saying Richard can't kiss Tina for the same reason. That's an insult to everyone concerned."

Convinced the unconsummated love affair was paying tribute to viewer prejudice, the actress balked at participating in love scenes restricted to longing looks.

"The kissing became a big thing on the set," said Guthrie. "I remember the day Wes Kenney came back from a meeting with NBC and announced 'You can do it." It was like the earth shook."

The new permissiveness didn't last long (three or four kisses over a period of a few months). Both Guthrie and Andrews said the mail was over-whelmingly negative and kissing quickly disappeared from the script.

"After that, we weren't even allowed to touch," said Guthrie. "Whenever we inadvertently worked it in, we were told to stop from the control booth. It was ridiculous."

"They would always say, Richard, don't touch her.'" said Andrews, "never the other way around. Pretty soon we started getting sripts containing stage directions like, 'They look at each other warmly, but they do not touch.' underlined five time so we wouldn't miss it. That offended me as an actress, as a woman and as a black person."

Kenney admitted the physical aspects of the relationship had been played down in the past but said the couple had again been allowed to kiss in more recent episodes. Referring to the "no touching" remonstratives, he said, "If I had seen directions in the script, I would have taken them out." As coexecutive producer, Kenney often edits the scripts before they are given to the actors. Former head writer Pat Falken-Smith, the creator of the interracial romance, disagreed with the young actor's assessment of the situation. The kissing and touching was played down, she said, as a matter of storytelling.

"In daytime programming, the drama is much stronger when you don't show intimate love scenes," she said. "If Richard and Tina thought it unrealistic that a young engaged couple didn't kiss, that's tough. It was my story and gratuitous kissing was not part of it. And no actor rewrites me on the set, ever.

"There was never any prejudice against a black story or against black people," she said. "I created the story, I hired and trained a black writer on the show and I had a black assistant. My credentials as a white liberal are impeccable. With the special sensitivity blacks have, they sometimes read things into a situation that simply aren't there."

Falken-Smith was fired from "Days" in April and said she is planning a multimillion dollar suit against the network for breach of her $680,000-a-year writing contract.

Surprisingly, Richard Guthrie bears the brunt of off-screen vilification for the black-white love affair. Nearly every veteran soap performer has a favorite irate fan anecdote, usually a variation on the theme of being pelted with oranges in the produce section as retribution for some ignoble act committed on videotape. But as a close friend of Andrews, the 25-year-old former UCLA drama student tends to take it personally when accosted by a fan confusing reality with illusion.

"I hate to see prejudiced people getting their way," he said. "It really hurts me for Tina.

"David and Valerie's story seems important to tell," she said. "There may be people who can benefit from its telling. Let the rest of the snow entertain. Maybe this one small part could educate. It's too bad the story is being dropped.

Tina Andrews is not surprised her days on "Days" are over. She is, in fact, surprised the role of Valerie Grant lasted as long as it did.

"When I joined the show, I know blacks had never been deeply rooted in daytime television," she said. "For that reason, I expected the job to be temporary, maybe only six weeks. All blacks on the show felt if we were meant to be on long, at least one of us would have been offered a contract.None of us was."

According to Kenney, at least half the actors on "Days" work on an "as needed basis" and without contract. Contracts are normally not offered, he said, until an actor has been on the show for at least a year.

Guthrie came to the show in July 1975, and signed a four-year contract two weeks later. Tina Andrews joined the cast in September of that year. Without a contract, Andrews is, in essence, not officially fired, just no longer needed.

Kenney confirmed the actress was leaving the show, but hinted there may be hope for David and Valerie in the future. He would not elaborate.

"We understand there will always be some resentment in some areas of the country toward black programming that becomes too intimate," said Kenney, "But I think both sports and show business have gone a long way toward breaking down these prejudices. I think all the networks have made a concentrated effort to incorporate more black programming. NBC started it all a few years ago with 'I Spy.'?

Ketty Lester, the veteran actress and singer who played Valerie's mother, Helen Grant, said she is not surprised to be out of a job, either.

"I'm not shocked by all this," she said. "I'm an old black woman. I have experienced discrimination every day of my life. I think the public didn't want blacks on the show, period. It's not NBC's fault, or Corday Production's fault. It show business: it's life: it's America. Richard can't understand because he's white. But I feel sorry for Tina if she thought things would be any different for her. She should know better. Things haven't changed."