User blog comment:ChishioKunrin/RWBY Volume 3 Livestream/@comment-1292715-20160211172703/@comment-10390252-20160211173239

My guess is that Taiyang and Summer never actually married. Maybe there is no equivalent of divorce in Remnant. Or maybe Taiyang just refused to let Raven go emotionally, even though he was living with Summer. The phrase 'abnormal family dynamics' seems to have been created for the Rose/Xiao Long household.