dan heng never had any interest in romance or love. and it's not like he needed to marry for power - xianzhou dynasty was one of, if not the most, powerful dynasties in the region. and, well, being a vidyadhara, he was subjected to a rebirth cycle and thus did not need heirs to his throne. a lot of reasons for him to not marry.
thus dan heng preferred to have concubines - not 'own'. he didn't like that terminology, and held respect for the women that he assigned as being his concubines. they were given all the wealth in the world, just in return for some loyalty towards dan heng himself. his favourites were given manors to live in, their own personal workers, etc. it was a dream come true for a woman reigning from poverty such as yourself.
and thankfully, you had struck gold. after being assigned as his concubine, dan heng had grown oddly infatuated with you. your witty personality and the way you were so... genuine made every little interaction he had with you so worthwhile. you were unlike the other women in his life, let alone his other concubines.
hence why you were 'chosen' to carry his children. it wasn't anything planned, but to dan heng, it was a happy miracle. he was even more pleased when you decided to keep them - two twin boys.
so now, as he sits on his zaisu watching you struggling to keep your two sons from climbing up your form, he was completely enamoured even if his aloof disposition remained. it didn't even matter that the children were pulling on your hair and making your robe look completely dishevelled. no matter what state you were in, to him, you were always beautiful. he had even laid his book down on his lap, his eyes devoted to soaking in all your features.