What we consider " objective moral truths'  seem to be based on' Jesus said so' - in the Gospel. A version of "The Bible tells me so'.

Strictly 'objectively' the moral truth for most people seems to be that people should not continue living together in a toxic relationship. 

Even St. Paul allowed for divorce in cases of a new 'believer' married to an 'unbeliever'  who would not live 'in peace'.