It's quite simple to understand that:
Here in this part you've said has the key about everything you said: "I started because I was cheated on by my first partner. Ever since I have “attracted” successfully a lot of girls."
You got into PUA and single life because of the pain of being rejected... The way you get into the PUA game was not only about the pleasure. The root emotion was that pain about being cheated... So unconsciously you kind of have tried to validate your masculinity hooking up with the high amount of woman you can. Your short term relationships and broken hearts you did may be something about: "Oh, I was cheated before... So let me be the one to cheat or to hurt someone feelings and break up, since this is definitely going to happen again. Then, doing that I don't have to worry about being rejected, cause I was the one that rejected her. I'm in some way in the control of the situation"
So being single or in LTR: the reason most of relationships doesn't work it's because we're broken inside (fears, traumas) and those traumas create some unconsciously behaviors... and those behaviors can hurt someone that trigger traumas and fears on that person, spreading it like a disease.
Women and men do all the kind of mistakes in relationships because they don't understand that and they did not solve their internal conflicts in the right way. When fear is dead, you don't have those worries anymore.
And, that may not be your case... But my life went somewhere similar than you. But maybe I had more intense and crazy experiences in my life... and it lead me where I'm today.
I was fat, then become fit and good looking at 17... The girls basically chased me in that period. Also I had a lot of relationships cause I felt in love really quick (since I was rejected until that age)... So the same time I have the hottest woman in my hand I lost a lot of stuffs dating some crazy chicks. Then I got into a 3 year relationship... I was so stupid, I left everything behind so in the end we broke up, I become the demon and she started to date some rich guys. Then I had depression, become fat and all the girls stopped chasing me, I was getting only the 5 to less (this repeated as I lost weight, then gained weight...). But in that time I met a girl... she is simple, she showed some genuine desire, she was completely different by all the patterns I was used to identify. So I'm risking it at that moment. On the worst period of my life she was there, and I think that may be something good. She helps me and I help her... It may not be forever, but the experience is worthing the prize until now (I'm 29yrs btw). I'm not up the idea of this being forever, I've learned that focusing on what I'm learning is more important then being affraid of what can happen. If something happen, just learn, recover and move on.
So after all that... What I suggest: Start learning from your experiences, enjoy it. The bad and the good ones... they will make you grow up. It's for a lifetime, you will always grow up. Some truths will hurt you so much, you will fall down sometimes, but if you're not dead, you can get up and you can evolve yourself with what you've been through. Without pain, you can grow... your mother felt a lot of pain during childbirth. Life is about that, pleasure and pain, happy and unhappy. If you decide to life on Ignorance, it's up to you... But you will be doing the same thing most of people try to do (run away from their own pain) and this will kill half of the learnings Life is giving to you.
I will never forget what
@Spaz said to me here in this forum: that we should learn by our experiences. That made so much sense when I understand what it means. I was relying my pains and doubts on books and other opinions, and I wasn't get nowhere. Now I can see the light on the tunnel... and it's becoming brighter as I face my good/bad experiences and go deep into my conscious.
Also this image for you, this is the biggest truth said on Star wars:
DON'T GO BACK MAN, GO FOWARD.