User blog comment:B214/Kuoh Academy students finding out that Issei stays with the ORC girls and is dating Rias./@comment-4547267-20131217014928/@comment-1359322-20131225031920

Issei won't try to do something like having an affair with his brother-in-law's wife. As for the reason why Issei didn't suffer any nosebleed or anything is because he was more nervous at that time, having the wife of a Satan wash his back.