Break up advice needed

So I basically haven't had a serious relationship in 3 years, this ex was violent and controlling and although I was only 18 at the I was madly in love. Eventually it ended, and I've spent the last 3 years enjoying life. I haven't had a serious relationship since, I've dated but never had that spark or romance with anyone.

Now coming up 3 months ago I met someone randomly, he was 4 years older than me we shared past experiences, I told him all my past experiences with my Ex and he understood. I told him I had issues trusting men, not wanting to get hurt ect. He emphasised how much he wasn't out to hurt me ect. We spent a lot of time together, got to know one another and really clicked. He'd send me flowers to work, ask how my day was ect.

Then after around 3 weeks he started to mess me around, we'd make plans and he would go out with friends and mess me around. But still emphasised how much he liked me and how sorry he was, and from then I needed constant reassurance that he wasn't going to hurt me. I dedicated myself to doing the things he liked because I wanted to be part of it.

So around about 3 weeks ago we got together officially, but he wanted to keep things quiet. He then became really nasty and controlling, disliked me having social media, disliked old photos from social media on holiday in bikinis said I was an 'attention seeker' being so blinded by this, I deleted whatever he didn't like. I think I suddenly became to available for him, because he became more distant.

Then over a week ago, he ignored me to text me the next day and tell me I wasn't for him and he wasn't that into it anymore and that was that. I was devastated, id put so much time and effort into it. I'd opened upto him, and he had promised he wouldn't hurt me then to do this. So I found a day later that the whole time I was seeing him he was sleeping with an 18 year old at the same time (he's 27 I'm 22). This kind of helped a little because i felt like I hadn't known that person at all, and it had all been a lie. I messaged him to inform him I knew, how dissapointed and disgusted I was for him to do that after I had opened up and put so much into it.

But even a week after finding out, I still feel so down and out about it. Wondering what's wrong with me? I put so much and offered so much to have someone do this to me. I feel so hurt. How do I move on from this and let it go?