Most Helpful Guy
There's no way to tell him without angering him, so you're gonna have to let go of that pipe dream.
Just tell him. Be honest. Brace yourself for the likely dump, and use this as a learning experience.
Most Helpful Girl
He's going to get mad anyway and honestly there's no easy way to say it so just tell him and get it over and done with the longer you take to tell him the more he will feel betrayed he'll feel because you kept it from him