how do you end a long term relationship

I’ve been in a relationship w/ my partner for almost 3 years and we have gone through a lot. at about 1.5 years in, I found out he had been cheating on me for the whole span of our relationship.. but I stayed with him because I loved him and was afraid to be alone.

Fast forward to now, we’ve been living together in my mother’s house for just under 2 years. I’ve caught him cheating on 2 other occasions but when I found out about the first time we agreed on the 3 strike rule. I never fully forgave him for it all, and it still eats at me. I have nightmares of it happening again, and I constantly stress about what he’s doing on his phone or who he’s with. I hate myself for not forgiving him and I feel guilty about it. He’s shown that he make a true and valid effort to not do it again so i feel like i can’t end it.

The other thing that’s been weighing on me is that I feel like I can’t live by myself. I haven’t been single and tried to find myself at all since i was in 9th grade and i’m a senior in college now. I feel like i need to do some soul searching and figure out who i really am. I also feel that If i stay with him ill be settling in a way.. people keep telling me that if a man really loves me he would show it from the start, i wouldn’t have to beg and plead for it.

i love him and i want him to be happy, but i’m not happy anymore; and i need to put my happiness first for once.

but idk how to break up with him. idk how to even start the conversation.. plus he’d have to keep living with me for at least a month in order to find a place to stay which will be hell.

any advice on how to break up with him would be greatly appreciated.