I'm thinking of leaving a date with a really nice guy because I ran into an old flame. All is fair in love and war
Why would you do that to the nice guy?
It's the both me and the nice guy deserve (or) It's the both of us, I love both of them
You cannot love both of them at the same time, you have to choose one. If you've fixed a date with one of them you are supposed to go for it. It's inconsiderate and selfish to ditch the date for someone else.
I'm a girl so it's fine, I'm allowed to be that way.
Just because you're a girl doesn't change the fact that ditching a date for an old flame from being wrong. I'm sure the nice guy would be upset to be ditched.