If he wants to break up with you, you need to accept that. You can't only love his good side and expect that he will be any different when he's not himself.

"he's been asking that we break up. On top of that, after he saw that I wasn't budging, he's been blackmailing me that if I don't accept him as just a friend,he'll remove me from his life completely. I honestly don't know what to do "

You can't complain of emotional abuse and blackmailing when you are doing the exact same to him. You're blackmailing him to stay in a relationship you both know is not healthy. He wants to leave you to protect you from his bad side, and you really don't want to stay with someone who is not only mentally ill but can cause you physical and emotional harm when he is 5150. I'm sorry, I do not believe he is your soul mate after only 2 years, and that's my thought on the best of relationships, but knowing he has violent and abusive multiple personalities is not in any means a quality of a true soulmate. You can't hold on to the good side and ride out the bad side when he can seriously harm you. If he wants to break up, you can't threaten him and blackmail him about it. That's not healthy.