When is cheating, cheating? When is it justified?

I was married to who I believed to be my soul mate.  After 4 years of me being the only bread winner,  supporting him,  paying his child support, lie after lie after lie, I divorced him finally.  He started seeing other people and I followed suit.  Then a year later,  we reconciled.  More of the same continued.  Tracking him to strip clubs,  his lies daily,  never contributing financially or emotionally to the relationship,  finding porn on his phone and cyber Sex. .etc. it was very rocky but I tried everything I knew to do.   About a year ago, while we were together,  I was raped.  He totally booked.  When he came back I needed support and communication.  He refused to talk about ANYTHING involving emotions and the lies got worse.  Then I became sick and Chemo was needed. He left me again. This time for 6 months and came back apologizing. The same behavior continued though. It all came to a head 2 days before New Year's Eve. We,  meaning I tried to communicate but all he would respond with was throwing in my face any relationship that I entered into during our 1 year separation.  Would never admit to his.  Finally I told him that I was through with the games and I had wasted 8 years waiting for something that I didn't even know what from him.  I told him that if he could not man up,  be honest,  try to work to fix our relationship then I was starting a new life without him.  He said I wasn't worth the work and we said goodbye.  A few days later,  on New Year's Eve,  I went out with friends,  cried most of the time,  but ended up being intimate with a lifelong friend.  My x came back the next day and wanted to start fresh.  I explained that it would take a ton of work,  we needed to be open & honest with one another,  and talk it through like adults.  His answer was deleting and factory reseting his phone,  my answer was telling him what happened the night before (first EVER screw up) . Now although he says that he wants to work through it,  he throws it in my face daily and demands an apology.  I don't feel as I've done anything wrong.  He refuses to believe that it wasn't JUST Sex,  that our underlying relationship issues led me down that path. I have felt so used,  alone,  and frustrated for so long. When he came back, after my rape,  briefly,  he quickly left again,  a couple months later,  when I found out that due to some medical issues,  I was to  go through Chemo. I felt abandoned, betrayed, & hurt. This is the time that I made a stand in my relationship. I told him that I needed a partner that I could trust,  depend on & build a healthy relationship with. I  made myself very clear that we needed to resolve this feeling of "relationship limbo" right the,  right then. I couldn't go on another day without knowing something!  He again,  refused any attempts at communication,  other than blaming everything on me,  then left saying we were through. I decided that it was best for me to attempt to get on with my life after months of him telling me that we were over.  I'm so confused and he is tormenting me daily with questions and accusations,  not to mention,  down right cruelty and emotional abuse. He tells me that when we make love,  he feels nothing anymore.  He had always unjustly accused me of many infidelities over the years.  I've tried to reassure him but it doesn't help. He tells me that what happened that night,  after he left me for the thousandth time,  just process that he was always right not to trust me. I am desperate for advice here!  Help me understand! !!!

...."I told him that I needed a partner that I could trust, depend on & build a healthy relationship with". These are your words and this is what you need. Deep down you know whether your ex is right for you or not and you well know if he's capable of being a caring partner or not. If he hasn't the need to be with you, then move on, as you have done in the past, and give yourself a chance to find a trust worthy and dependable partner as you state. Actions speak, while words are just words. And no, cheating is never justified in any relationship. The trick is to be tough enough on yourself and be well and truly over your ex before venturing anywhere else.