I think this song is clearly about a man who is cheating on his wife with either one of her realtives or a close family friend who is Rose, that is staying with them. Obviously him and wife don't have a good relationship that is why he's referring to her as a snake. He starts this affair with this woman thats staying with them. They have sex when the wife is sleeping and when she goes out of town. For him its more than sex now and he's falling in love with Rose. He wants to leave his wife Mary and start a relationship with Rose. But, he seems to want this more than Rose because he keeps having to convince her that their doing the right thing. I don't think Rose wants to hurt Mary.
I think this song is clearly about a man who is cheating on his wife with either one of her realtives or a close family friend who is Rose, that is staying with them. Obviously him and wife don't have a good relationship that is why he's referring to her as a snake. He starts this affair with this woman thats staying with them. They have sex when the wife is sleeping and when she goes out of town. For him its more than sex now and he's falling in love with Rose. He wants to leave his wife Mary and start a relationship with Rose. But, he seems to want this more than Rose because he keeps having to convince her that their doing the right thing. I don't think Rose wants to hurt Mary.