Mature cuckold man cheated on his fiancee with her bestie. Will the 18 year old naive girl find out?

A mature cuckold - Man, felt the need to Snapchat his fiancée's best friend. At the time, his fiancée didn't know anything about it. Her best friend agreed and simply let herself be fucked without a condom. Will his fiancée be mad or will she enjoy being cuckolded?