Sister, his choices are likely a results of character flaws and childhood trauma that went unresolved forever.
That is a thing, common in cheaters.
This doesn’t excuse the sexual and emotional abuse he inflicted you with infidelity, adultery, betrayal.
This is a trauma gifted just for you, and a very bad one at it.
You see there are usually reasons for bad choices, rarely a person is completely rotten or evil. Most of all had troubles and little or big traumatic experiences that developed character flaws.
Most people find healthy copying mechanisms. Some resort to evil and abuse, because they are too scared to accept their issues and confront them.
Imagine for example I come and tell you the story of my childhood abuse trauma etc. then instead of facing the issues or finding a healthy coping mechanism, I end up abusing sexually another person. (Or any kind of abuse really, this just got our case)
Does that make me the victim even if I started being one? Does it justify the abuse in any way or form? No, it doesn’t. 2 wrongs don’t make a right. Evil choices are still bad no matter if they come from hurt, you are still the villain.
The abuse received is a tragedy. The abuse inflicted is a deliberate choice.
If you weren’t emotionally invested in your partner you could see this clearly and you would not excuse it in the slightest.
The tricky thing about infidelity is that we love our partner, so even as abuse victims we try to find empathy and excuses just to deny the closest person in your life could do you one of the most horrible things a human can do to another human.
That’s why nasty ptsd is so common and some people break completely or end it in the worst ways.
That’s why is important to see the betrayal for what it is and the cheater for who they are.
You need to put yourself first, set boundaries and protect yourself from further abuse to get you time to heal from your wounds.
This is not an upside or a small blunder. The damage to your nervous system shares similarities with other nasty sexual or emotional abuse, just know those are punishable by law, you would probably never receive any vindication.
Maybe scorn, which adds insult to injury.
Friends are good, but unless you’re friend with someone who dealt with infidelity in their life, they won’t be probably much helpful, is a complex topic and an uneasy one, as it puts into jeopardy the deepest form of human connection, the attachment wound, it’s something you don’t really want to think about or face unless your are so "lucky" to find you into, your partner’s courtesy.
Still like all trauma and abuse there is a way out. The most straightforward is removing yourself from the abuser and cutting them off your life. Which is the most common advice you get from the average person.
Problem is, you most like,y have emotional attachment that doesn’t make it so easy to cut it off. And that’s something people who didn’t live it, cannot understand.
It can put you in the position of a special kind of lonely and mess with your mind and emotions.
Think this.
You suffered a great wound and you are likely living with chaos right now.
What is important is for you to be heard.
You have been heard.
Start acting to protect your own emotional state (what’s left of after the nuclear blast) in writing down what you want what you need, what you deserve. Those are your boundaries
They are more important than ever right now.
You come first.
And let out all the pain you feel, don’t compress it. Here you will find people who can hear you and understand you