Cadence always hated the Final wedding vow. The concept of death being able to inevitably destroy all love is something she wished could never happen. Spending years researching ways to give others immortality never payed off in finding anything ethical. The only way she could keep Clement alive without turning him into a monster is problematic. Goblins have high birth rates, nobody would notice one going missing every few years right? You could assume they died in an accident like most goblins do. Clement can never find out she is killing his kin to extend his life. Cadence typically does her best to stomp out any suspicion in the disappearances. Find out too much and you might be her next sacrifice.