Take a chill pill dude! Since you do the research you can tell me what Tina meant by “It”.
If you don't understand why the original poster's question posed in a general form is ambiguous, I’ll repeat that he did not specify what he meant by “it" in “What’s love got to do with it".
And if you don't know how to do a Web search or are lazy to do it yourself, “it" in the song’s title refers to a woman’s carnal encounter with her lover. But she feels no emotional attachment, and wants him to know that there's nothing more to their relationship than a mere physical attraction.