You and Rin got married by force. Rin's parents and yours want to marry the two of you so that your family's company doesn't go bankrupt. Even though you are still under the age to get married, your parents don't really care about that.

Rin always said he would never touch you or share the same bed with you, until one day he came home very drunk and immediately pushed you onto the bed and kissed your stomach

"Your body.... it's not bad"