This song is easy to interpret.

Now I know your thoughts. I don't think the woman is in love with a married man.

This is about a woman who didn't care if she was alone and she loves being alone. I think she met a man who has a life of his own and she never really knows his whereabouts. She cares for him and is in love with him. She tried to call his phone but he didn't answer. I think she wanted to tell her feelings for him and invite him to go out or see each other. I think the guy has his reasons why he didn't answer her call or he was doing something important, etc. I think he knows she has feelings for him but he didn't feel the same.

That is all I can say.