rule #1: dont cheat when you share the building with your boyfriend's friends.
rule #2: dont use the same lies you told your boyfriend you used. for example: if you tell your boyfriend that, at work, you tell people that your hickeys are bruises from playing paintball, dont then tell your boyfriend that the marks on your neck are from paintball. thats just dumb.
rule #3: dont try to be nice afterward. there is no afterward. bye-bye with you.