Why Yugi/Tea?

Personality Match

I've always perceived Yugi and Tea as being sort of a "duh" couple--I mean, sure, they're going to be together. Why wouldn't they? For me, they are one of the most canon (proven or reliable) couples in the whole show, simply because there is a lot of mutual respect, trust and, yes, love between them. Sometimes more can grow out of friendship, and if couples are going to stay together a long time, they better have some kind of common ground. There isn't just sexual passion between them, though even in the dub there are hints of that lying dormant below the surface of their friendship. Indeed, their bond is a complex one, but those usually last the longest time.

Long-Standing Friendship

Of all the girls in the cast, Yugi has known Tea the longest, and seems to have formed a much deeper bond with her. He trusts her instincts about people, and often depends on her for emotional support; she appreciates his guidance in both Duel Monsters and life, and takes his advice seriously.

Other Theories

Though some would say Tea likes Yugi's "other self" (Yami Yugi) more, I have a different theory; I believe Tea sees in Yugi the man he will soon become--and Yami is a very close match to Yugi's future persona. Yami is only two or three years older than Yugi himself, and throughout the series, Tea's encouragements and Yugi's own positive experiences help him overcome the shyness that stands in the way of his becoming a leader like Yami. It is his metamorphosis from young boy to young man that seems to be the attractant for Tea--and if she were a real person, we may even say that she psychologically seems to need to help him become the man he was meant to be (and the young man she's seen in him all along).