Is letting a friend fuck her in the butt not considered cheating

A good-looking guy went to visit his friend. A guy is standing next to the girl and persuades the beauty to do a completely different matter, instead of being boring to sit and look at her boyfriend. The lady smiles pleasantly and it seems that she has a thought on her mind for a long time to have sex in the ass. And then the beauty dares and decides to have anal sex. She goes to the bedroom and, kneeling down, the beauty begins to give a blowjob to a friend, and completely forgets about her boyfriend on the couch ...