My boyfriend of 2yrs cheated on me in a very painful way and cries he loves me and never wants to leave me. We got back together after a while but I haven't been the same since then. I've grown so paranoid and he still wants to see me through it. I still love him but am not functioning right. I shout and scream at him for anything. How can I get over him before something happens.

Counseling! Go to counseling by yourself or if you want to stay in the relationship, go to counseling together.

No trust = No relationship

Don't force yourself to stay in a relationship that is bound to end when there's no trust and that the trust doesn't seem to be able to be repaired.

Furthermore, you definitely need to distance yourself from him so that you can spend more time focusing on yourself. If you can't break up, you still need a break from him to gain some perspecitve. Your priority should be taking care of yourself.

Most likely, you will never get over the fact that he cheated on you. If you choose to stay in the relationship, you both will be paying for his mistake. Take some time for yourself. End all this anger, its not helping you, its unhealthy.

Once a cheater always a cheater. You cannot have a relationship without trust. It will always be at the back of your mind no matter what he does or says.
An ex told me one: "just because i cheated on her doesnt mean i dont love her. he was a serial cheater." he obviously doesn't love anybody the way he loves himself. Once you cheat, its always easier to cheat again. I was always paranoid and never trusted him completely.
When you are dating someone, you need to be able to trust them, no matter what situation they put themselves into. It is the sense of peace and security we should be entitled to in any relationship. Trust is vital and cannot be absent in a lasting relationship.
If you feel that you cannot trust him, either take a break to assess what you want from this relationship and what he can provide you; or you need to leave this guy. I know 2 years is a long time, but think of all the years of paranoid that is ahead of you if you decide to stay with this guy.

Counseling will help, but you may need a long break form him, as this relationship has turned toxic to you both, because of his actions.

Sorry for your situation, but you don't recover from emotional trauma in a while, without help, and he doesn't know how to help.