Obviously about John loving some girl but shes leaving him, and hes saying don't. He seems too clingy in the song, which could explain why she is leaving. He loves every little part of her, he keeps asking questions about their relationship, and where has she been. and then he accuses her of cheating on him.
A little little could be "stay a little longer." You will when you won't could be her saying she'll met him somewhere or do something with him and she doesn't show up, but he still doesn't want her to go.
In summation:
The singer's girlfriend gets tired of him being so clingy all the time and starts not showing up to dates and he becomes erratic and accusing.
Obviously about John loving some girl but shes leaving him, and hes saying don't. He seems too clingy in the song, which could explain why she is leaving. He loves every little part of her, he keeps asking questions about their relationship, and where has she been. and then he accuses her of cheating on him. A little little could be "stay a little longer." You will when you won't could be her saying she'll met him somewhere or do something with him and she doesn't show up, but he still doesn't want her to go. In summation: The singer's girlfriend gets tired of him being so clingy all the time and starts not showing up to dates and he becomes erratic and accusing.