User blog comment:B214/Volume 17 spoilers./@comment-67.176.158.104-20140320221310/@comment-24468758-20140321152758

And the girls are just playing around most of the time since they all acknowledged Rias as the legal wife from the beginning and they will most likely let Rias get all of Issei's important first times so they can't get serious unless Rias already reached these stages.