Hi ff4152, one of the things I've always liked about you, and not understood very well, is how you keep expecting people to be kind to you, to help you when you need help, and keep getting frustrated by them. It has come up over and over in your posts. Why are you so eternally optimistic, and always disappointed? I have wondered about it. I've wondered because I have a different dynamic and yours looks so foreign to me.
Here's my armchair psychology, since I know how suspicious you are of IC and probably not talking to one right now (you have the same dynamic with them, don't you? Worried about it, put yourself out there, expect help, get a little, then they always disappoint you and/or try to kill you).
If I remember correctly, your mother remarried when you were 4. So up to that age, you probably had a more or less responsive mother. She helped you when you needed help, loved you, etc. After that, she married your awful stepfather. And he was horrible!! I am so sorry for how he treated you. And even worse, he seemed to treat your siblings well, so you had the feeling that it was somehow your fault that you were the scapegoat. But worse than your stepfather's treatment was your mother not defending and protecting you. The things you have written turn my stomach. No mother should tolerate her child being treated that way by a man, let alone bring him in the house and witness it over and over without making it stop. i am so, so sorry that happened to you. So that set you up for this dynamic you experience over and over - you know that she can love you, can protect and help you (up to age 4), and then she stops (after age 4). You both expect to be loved and dread it being taken away, being left on your own and vulnerable.
With your friends and family, i suspect you set up tests for them to try to precipitate what you dread happening. like posting photos on facebook that show you need help or attention, then being upset when they don't reach out. And you probably communicate that demand and expectation and frustration, and they intuit it, and avoid you. And I'm sure you can see that pattern with your relationship with your wife and the affair.
That's not to say that they are not wrong, difficult, self absorbed, or at the very least imperfect. They definitely are. But your experience of it is worse than it needs to be, because it's a replay of your existential crisis, and you are probably also seeing things that are not really there.
So what to do? When i notice my old patterns replaying, the noticing itself helps, some. it doesn't make it go away but i can step outside it a bit. Feeling all those lonely and misunderstood feelings from when i was younger helps - i didn't give them any space then, because i had to march on. you have to re-experience it, feel it, to start to heal it.
another thing that helps is talking it over with someone who is not in the middle of it. my husband is my reality check when i'm losing it, and i'm his when he is experiencing old patterns (his are very different from mind, and easy for me to see, hard for him to see). When you're re-experiencing it i think you literally don't see reality clearly. Someone to help you really see what's going on can help so much, especially if they know your patterns.
IC, of course, and you can talk to the IC directly about your suspicions that they are going to let you down. if that feels terrifying, or hard, or if you avoid it, you know you are in the right ballpark.
And my SI friend, i have to be honest, the thing that really has helped me is religion, prayer, spirituality. My IC gets it wrong, my friends get it wrong, and my husband despite all he wants to do for me gets it very wrong sometimes (cue the song jesus is my only friend by sweet honey in the rock. i love that song). i remember a day i was just miserable, lonelier than i had ever felt before, and i went up to the church i used to go to every day to cry and felt such an enormous comfort. it took a long time to get there - luke 11 on persistence, months of it! but it's the only REAL help there is. The people who care for me (imperfectly) are showing a reflection of the perfect care, and when i experience that it's healing.
Hope that helps ff4152. i really hope you can find another way to keep growing.
(sorry for the erratic caps, my shift key is sticky)