I think this song's about a woman who is in love with someone else's man. I think she's mostly fantasizing about being with the guy; I don't think she's made attempts to start an affair with him. They seem to only be together in her dreams (from "tonight you belong to me" to "I know with the dawn that you will be gone". It's like he's her lover in her dreams at night, but in real life he's with someone else.
I think this song's about a woman who is in love with someone else's man. I think she's mostly fantasizing about being with the guy; I don't think she's made attempts to start an affair with him. They seem to only be together in her dreams (from "tonight you belong to me" to "I know with the dawn that you will be gone". It's like he's her lover in her dreams at night, but in real life he's with someone else.