[18M] Trying to navigate reconciliation with ex [18M]. I feel like I'm not doing enough

A year ago I met my ex via social media. We started talking and it led us to becoming an actual relationship. It started off well, but it got sour after a month.

Sometimes he'd constantly ghost me out of nowhere whilst knowing my past struggles with getting ghosted. He also 'forgot' I was bisexual and gave me hell for it with constant accusations of cheating and just overall being a dick. He'd lash out at me over small, minuscule things he'd admit he'd never get mad at anyone else for, and was overall terrible.

I won't act like I was pure of heart either, when he (I'll call him Justin) ghosted me for a third time I had enough and was already going through it mentally. I figured that if he treated me like this constantly that meant he didn't love me, and overall I was tired of being the bigger person in general. I cheated on Justin, I'm not proud of it, but I'll admit it. I got my revenge and I regret.

He rightfully got pissed because: "Despite everything, I was loyal to you." Which, to his credit, he was. (I have a history of getting cheated on)

Ever since then I've been focusing on myself; I've indulged in literature started reading and writing for fun, and started casual dating to learn healthy rejection and too stick up for myself.

A week ago Justin sent me a message apologizing for everything, about how he had no right or reason to treat me the way he did. I accepted his apology and things have been mostly calm since then, though I'm still afraid that he'll lash out on me again.

I know it's on BOTH of us to fix the relationship despite everything, so I have to ask what should I do? So far I've been distant and cautious and I feel like that's disrespecting his growth since he's finally displayed the fairness and maturity I begged for when we were together.