User blog comment:Xilinoc/Ch. 651 - The Theatre Suicide SCENE 5/@comment-29449108-20151113223353/@comment-5398287-20151114170408

The curse seems to be very specific - any men who enter the Ise family line, via marriage, die shortly after doing so. Apparently, just living together is fine, although given the customs of Soul Society, and likely by extension Japan, I don't think they would've been looked upon with understanding and compassion if they had Nanao out of wedlock.