Martin Luther King suffered a secret heartache

She would hang out and watch as he played pool and table tennis with his friends, he'd take her for drives, and even out for meals when his student budget would stretch.

Best of all, they would simply sit on a bench and talk, and talk, and sometimes kiss.

In the years before he became a civil rights leader, an icon who would ultimately sacrifice his life for his 'dream' of equality, Dr. Martin Luther King Jr. was like most other 20-year-old college boys in 1949, trying to woo their girl.

Except, even then, King wasn't really like every other college boy.

Even then, the passionate man dared to dream big. Because his girl, the legendary civil rights activist's little-known first love, Betty Moitz, was white.

 Betty Moitz was a young art student who met Martin Luther King Jr as he studied to become a pastor, and became his girlfriend

And that fact, even away from King's Atlanta home in America's then brutally segregated Deep South, in the more liberal north of America where he attended college near Philadelphia, would still have unsettled or incensed most who spied them together.

Although segregation might have been outlawed there in schools, cafes and bars, when it came to love, the line between black and white was still heavily drawn.

It is little wonder few ever knew about that early, almost secret, chapter of his life – because ultimately, even King himself was forced to accept this was one dream he would have to relinquish.

Society, neither within black worlds or white, would allow him to marry Betty and live in peace.

Rev. Pius J. Barbour, a friend close to Dr. King at the time, admits it was a realisation which left the idealistic student a “man with a broken heart.”

 Martin Luther King had his heart broken when he was still at college

“He never recovered,” he later recalled.

King, the son of a Baptist minister in Atlanta, Georgia, had grown up under the vice-like grip of segregation across the southern states.

Although from a well-off middle-class family, he had experienced the humiliation of being forced to give up his seat on local buses for white people who stepped onboard; of being barred from playgrounds, libraries and schools only open to white children.

Somehow, he knew he had to lead a change, and aged 19, after majoring in Sociology at Morehouse College, in Atlanta, he decided to attend Crozer, a Protestant seminary in Chester, near Philadelphia, to train to be a pastor in his father's church.

This, he decided - although of course unable then to envisage just how central he would become to the civil rights movement - would be his path to making a difference in the world.

 Martin Luther King met Betty when he was training to be a pastor

And it was there he met Betty, an art student whose family lived on the college's campus.

Her mother worked as the college's nutritionist, and it was in the kitchen on a visit, Betty first got talking to the charismatic 'ML', as he was then nicknamed.

A few months later, they begun dating and things grew serious.

“We were madly, madly in love, the way young people can fall in love,” Betty revealed in 2016, before she died aged 89.

The interview she granted to author Patrick Parr, who spent years trying to track her down as he researched his book The Seminarian: Martin Luther King Jr. Comes of Age, was the only one she ever gave.

She described how captivated she was by King – as the world was also one day to become.

And how she fell for his ambition and idealism.

“I listened and he’d just talk and talk... He was wonderful - a joy to be with and listen to,” she explained.

“One thing ML knew at age 19 was that he could change the world.”

 Betty says Martin Luther King knew at age 19 that he could change the world

A few of King's friends and fellow students have also shed glimmers of light on the blossoming relationship over the years.

Marcus Wood once described how King “used to go over their house quite often to see her.”

“I supposed he thought that, here I am out of the South now, and not back home, out in the open, nothing illegal, a free place, sure I can go over and talk to this white girl,” he added.

“King was extremely fond of her... He was also rather proud of the fact that he was able to socialise openly with a white girl.”

But while King and Betty certainly weren't doing anything illegal, interracial marriage was still illegal in other states.

Their relationship wasn't the norm; even in their liberal community they would still have prompted stares, comments and unease.

 Martin Luther King Jr speaks to supporters from the steps of the Lincoln Memorial in 1963

Almost a decade later, in 1958, polls still showed 94 percent of white Americans disapproved of interracial marriage.

And it was only in 1967, a year before King's assassination, that it finally became legal for black and white people to marry in every state across America.

King certainly didn't hide his relationship from the community, although the couple weren't overt in their affections.

“We did go out on dates,” Betty said. “He was always trying to get me to go with him to restaurants in Chester.”

She herself maintained she was never conscious of the problems their presence might have posed – shrugging skin colour off with the throwaway comment: “I never noticed. I always had a tan and dark brown hair.”

She was actually more edgy about eating out...

“I was embarrassed to let him know I had never been to any of those places. In those days, who went to restaurants?” she laughed.

But King clearly became increasingly concerned about how their relationship could progress.

Although his friends were largely accepting, some warned him it could damage his future if things developed further.

If King wanted to return to the Deep South as a pastor and fight for black civil rights, he knew deep down even his own community would struggle to accept his white wife.

Tellingly, it seems he didn't even tell his own family he was dating Betty.

Even when his close sister Christine visited, Betty would retreat. It was because King worried about his mother finding out.

“He was worried what she’d think,” Betty said.

Initially, he pushed away his friends' worries.

 MLK delivering his famous 'I have a dream' speech in 1963

Wood recalled: “The more we warned [ML] that marriage was out of the question - especially if he hoped to become a pastor in the South - the more he refused to ‘break off’ the potentially controversial relationship.”

But it seems he slowly began to realise that this one dream, of marriage to Betty, might wipe out his other dream of changing the world.

An older, married friend, Horace Whitaker, recalls King speaking to him about the situation and seeking advice.

“They were very serious,” he remembered, “although he was young.”

“I’m not saying he wasn’t mature enough for that kind of experience,” he added

“But I remember talking to him about that kind of marital situation … and we had talked about it from the standpoint that if he intended going back to the South and pastoring at a local church, that that might not be an acceptable kind of relationship in a black Baptist church, and I think he would be valuing that in light of whether or not it was a workable situation, knowing his own particular sense of call.”

Certainly, at that time, marrying Betty would likely have ruled out King returning to the segregated South at all.

 Dr. Martin Luther King and his wife Coretta Scott King in 1964

The soul-searching which must have gone into his decision to end the relationship was surely painful.

But how painful, and how long that pain lasted, we will never know.

King, who in 1953 married Coretta Scott King, who he met after graduating, only remarked once publicly on the situation, in a 1964 biography by Lerone Bennett, What Matter of Man.

His quote is brusque, and practical, and gives little away – except perhaps, that even then, the future Nobel Peace Prize winner had an unbending sense of purpose.

“She liked me and I found myself liking her,” he said of Betty.

“But finally I had to tell her resolutely that my plans for the future did not include marriage to a white woman.”

It was a devastating acceptance which must have dented the optimism of the young activist – or maybe, also, spurred him on?

In 1963, in Washington, he told packed crowds marching for equality of the famous dream that would cement his place in history.

Of black people and white he said he hoped one day: “We will be able to work together, to pray together, to struggle together.”

Underlying it all was surely a dream we would one day be able to love one another, freely and openly, too.

Would you rather be the hero or the sidekick?