Faith was not something that was lacking in Gojyo. He had, had faith in his elder brother. He had faith in his friendship with Hakkai. Faith in his fighting skills. Even faith in his back-handed older brother relationship with Goku. But the most important thing he had faith in was his love for Sanzo. And the faith that Sanzo loved, truly loved him back.
He had been very forthcoming in telling Sanzo about his past, yet the priest never left his side, never faltered in his love for the taboo child. Gojyo loved the way Sanzo had simply cuffed him on the back of the head and called him an idiot, then softly kissed him, telling him it did not matter one speck that he had used his body to survive. Sanzo had even gone so far as to tell him he was grateful that Gojyo had done so for the priest had no clue what to do when they made love.
Gojyo suspected that his beloved had not told him the truth of his being the first to use the lithe body, but it mattered little to the loving red head. He was the one that Sanzo chose to be with, now and forever.
Faith sealed them together. Faith made two broken people one whole person. And come hell or high water he was determined to keep it that way.