IT'S OFFICIAL . . . Shantel Jackson And Floyd Mayweather . . . ARE MARRIED!!

the GREATEST boxer in the history of the sport, was considering marrying his longtime GF Shantel.

The two had been through a lot. But Shantel always made it CLEAR that she loved the champion UNCONDITIONALLY

And now they're "married." Floyd, we're told, does not BELIEVE in traditional marriage, so the couple opted for a new "no paperwork marriage." Under their no-paperwork marriage, the two have the same SPIRITUAL AND EMOTIONAL COMMITMENT as any other marriage.

But Floyd doesn't have the same WORLDLY LEGAL obligations as "traditional" marriage.

Congrats to the happy couple.