He clearly says sell me a coat because "I feel good."
So it's not him buying the coat for the girl.
I think he's resigned himself to the fact that he has lost her to Jack Frost, who I feel isn't another guy. I think he's saying that she literally died of freezing to death in the bitter cold.
But you're right, it was a fling, and so she doesn't really mean anything to him. So he can move on as easily as just saying, "Sell me a coat, 'cause I feel cold."
He clearly says sell me a coat because "I feel good." So it's not him buying the coat for the girl. I think he's resigned himself to the fact that he has lost her to Jack Frost, who I feel isn't another guy. I think he's saying that she literally died of freezing to death in the bitter cold.
But you're right, it was a fling, and so she doesn't really mean anything to him. So he can move on as easily as just saying, "Sell me a coat, 'cause I feel cold."