Hi Sparky0426 and

One way to help let go is to understand how much of the behavior exhibited by our BPD loved one is dictated by their disorder. It makes their hurtful behavior less personal, although it is still very personal.
Throughout the entire relationship he has broken up with me countless times.
Another consideration is that each time he broke up with you and reconciled, in a sense your psychological attachment increased. I've read it described as "trauma bonding" but a short description of this experience is that each shock (or trauma) cemented your attachment to him further. Even though he was the cause of this shock/trauma. It is the same reason why people who experience/survive disasters together feel more bonded together.
Whenever I would stand up for myself against his constant criticism he would abandon me, and manipulate the situation to make it seem like i was overly sensitive or i just "always need to have a problem"
Whenever you stood up for yourself, he registered it as the potential that you might leave him (or abandon him). And so in order to avoid abandonment, he had to abandon you first.
He intentionally antagonized me. He has blamed me for everything, meanwhile he is the main source of all conflict. He has.NEVER EVER apologized to me for any of the cruel things he has done, and never expresses any sign of remorse; in his brain he truly believes he is perfect and I am a horrible, evil person. Its crazy to me!
People with BPD (pwBPD) exhibit "splitting" behavior, also known as black and white thinking. In the mind of a pwBPD, other people are either "all good" or "all bad" and this perspective can change quickly. This is why he either "loves" you or else he "hates" you with no gradient in between.
This black and white thinking applies to their self perception as well. He *needs* to be perfect because the only other alternative is to be worthless and self-hatred. He can maintain the perspective that he is "perfect" by projecting all the negative qualities onto those close to him (i.e. you).
He antagonizes you to provoke you into exhibiting the same feelings he cannot manage and is denial of. When he provokes you, then in his mind, you are the one with the problem and not him.
At one point I was very much in love with him, I am a completely loyal and faithful partner. But throughout the entire relationship there were constant accusations that i was cheating, calling me names, etc ive been defending myself for 2 years.
In my observation, one of the big (unintuitive) triggers for pwBPD are feelings of intimacy and closeness. So perhaps, whenever he felt particularly close/intimate with you, it also triggered in him the fear that you would abandon/betray him. This is why he constantly accused you of cheating. In his mind, he felt certain that you would. And this is because of his disorder.
I have just severed all communication and I am so ready for this turmoil to be over with. I just dont know how to let him go, he has some unexplainable hold over my emotions and I need it to be gone.
One way is to get help. Find someone (even someone professional / i.e. therapist) who will support you in doing something that you alone cannot do. In a sense you need to be committed to disengaging from him. And seek support from people who will help reinforce your commitment to disengage.
Best wishes,
Schwing