The speaker is expressing gratitude to someone whose presence has brought happiness into a life that also contains sadness. At first, he hesitates to say what he feels, but decides the other person should know. The repeated refrain makes his appreciation grow more emphatic and joyful.
โJoy inside my tearsโ brings happiness and sorrow together: the speaker may still feel pain, but love or closeness has made that pain easier to bear. โMade lifeโs historyโ is an unusual, poetic way to say that this person has created a deeply important moment or changed the speakerโs life. The contrast between โyesterdayโ and โtodayโ also suggests choosing to live in the present rather than letting fear hold one back.
The song does not explain what caused the tears, or whether they represent a particular loss, hardship, or simply strong emotion. The personโs effect is presented as extraordinaryโsomething โno one thought could beโโbut that may be heartfelt exaggeration rather than a literal claim. Overall, the lyrics celebrate a relationship that can bring happiness even when sadness has not completely disappeared.