I could easily be wrong about this, but I think the song is about an affair. She's a woman who is afraid of commitment, and she is having an affair with the "muffin man" who tells his wife that he's at work. She keeps stringing him along and telling him that she could love him, and he doesn't want to leave his wife if it's not a sure thing, so he is ending it, but he still misses her.
I could easily be wrong about this, but I think the song is about an affair. She's a woman who is afraid of commitment, and she is having an affair with the "muffin man" who tells his wife that he's at work. She keeps stringing him along and telling him that she could love him, and he doesn't want to leave his wife if it's not a sure thing, so he is ending it, but he still misses her.