I think this song is about an affair. They met when her car broke down. He's married, and is very much in love with his wife, but also with her. This isn't a one night stand kind of deal, more like a long-term, fully emotional relationship. She's saying the day is bittersweet in that it has to end, they can't be together. She doesn't expect him to leave his wife - she understands the situation, but he lets her down in some other way. At the end she's saying she never thought they'd end up like this; she is bitter about his actions, but still in love despite this. I think I'm the only one who sees it this way, and it may very well be wrong. But it's my take.
I think this song is about an affair. They met when her car broke down. He's married, and is very much in love with his wife, but also with her. This isn't a one night stand kind of deal, more like a long-term, fully emotional relationship. She's saying the day is bittersweet in that it has to end, they can't be together. She doesn't expect him to leave his wife - she understands the situation, but he lets her down in some other way. At the end she's saying she never thought they'd end up like this; she is bitter about his actions, but still in love despite this. I think I'm the only one who sees it this way, and it may very well be wrong. But it's my take.