It's Clearly Lorraine 

A local man had a girlfriend whose name was Lorraine. She was 
very pretty and he liked her a lot. One day he went to work to 
find that a new girl had started working there. Her name was 
Clearly and she was absolutely gorgeous. 
He began to like her as well, and after a short while it became 
obvious that she was interested in him too. But, he was a loyal 
man and he wouldn't get involved with Clearly while he was still 
going out with Lorraine. 
He decided that there was nothing for him to do but to break up 
with Lorraine and date the new girl.  He planned several times to 
tell Lorraine but he couldn't bring himself to do it. 
One day as they were walking along the river bank, Lorraine 
slipped and fell in to the river. The current carried her off and 
she drowned. 
The man stopped for a moment by the river and then ran off 
smiling and singing... 
"I can see Clearly now Lorraine is gone..."