Ronaiah Tuiasosopo is gay ... at least he thinks he's gay. That’s what he told Dr. Phil.

Phil appeared on "Today" this morning ... and dished about his interview with the man behind the Manti Te'o not-really-dead girlfriend hoax.

"Here we have a young man that fell deeply, romantically in love," Phil said of Ronaiah.
"I asked him straight up ... was this a romantic relationship with you? And he says, 'Yes.'"
Phil continued ... "I said, are you then, therefore, gay?  And he says, 'Well, when you put it that way, yes.'" Phil says Ronaiah then "caught himself" and said, "I am confused."