Let me use scripture ma, since that’s the way I have been helped:
Luke 17:1-4
[1]Then said he unto the disciples, It is impossible but that offences will come: but woe unto him, through whom they come!
[2]It were better for him that a millstone were hanged about his neck, and he cast into the sea, than that he should offend one of these little ones.
[3]Take heed to yourselves: If thy brother trespass against thee, rebuke him; and if he repent, forgive him.
[4]And if he trespass against thee seven times in a day, and seven times in a day turn again to thee, saying, I repent; thou shalt forgive him.
Meaning, I should expect anything from anyone and be willing to let go, since Christ forgive me my own trespasses too.
And if the person will not admit their fault or apologise, still don’t let it affects you.. because eventually, all things still boils down to you.
While you are nursing in forgiveness and bitterness, the person met with the Lord, and didn’t even remember he/she did something wrong in the past and have moved on, you will be there alone with the pain.
In a nutshell, betrayal is inevitable, either by family or not, the sinner we settle with that, the less betrayed we will be when faced with betrayal.
My opinion.