Should I be good or should I be bad?

Description: Sitting in church today listening to my boring husbands sermon. a handsome man sitting in the pew next to me slid me a note and smiled. i picked it up and slid it into my purse and of course i smiled back. when i returned home i read the note. it said "you look amazing. lets fuck. call me". the man is my best friends husband. what should i do?