The way I see it, both are at fault. Sayn has to take some responsibility, as he had plenty of chances to tell the guest to GTFO and find somewhere else to stay, but instead he offered him a place, fed him, gave him drinks, and let him fuck with his woman while he slept. Most guys wouldn’t go to bed while their partner is still up with another man in the house, especially when alcohol is involved. Hopefully, he’ll learn from this and avoid making the same mistake in future relationships. Elli is equally at fault she should have ended one relationship before starting another, but her skanky behavior makes one doubt her judgment.