My current situation i feel hopeless

Hello

So I have been following EBP steps and reading as there is change with hard work to get my ex back.
I want to hear your feedback and if there is change for me from these steps.

I try to explain as good as i can. If question please ask as English is not my main language.

I am 26 and she is 27. We both have similar hobbies, down to earth peoples, with strange sense of humor (every guy would love her for this). We moved in very fast and it was also a bit overwhelming for me. We had been together like 3-4 months and we decided to buy apartment for us. We went out on trips and had pure excitement in our relationship. We where very attached to each other and did not have many friends as we are both new to this city and persons who are not very social. The sex was good, even tough i sometimes have problems with going soft as i have huge problem for overthinking during sex (keep this in mind for later)

So a year in or so, I went to the bad side and started to chat with other girls on meeting sites. I send nudes and receive them, told that how i am being used and not looking for the relationship. I was playing stupid and tried to get attention. I had no desire for physical connection with any of them, i wanted some excitement. I stopped it sometimes and few times write them back etc. At some point all came out and she saw the pics and texts. She threw me out for few days and we talked things over and i truly pledged my love to her and it was something stupid I did.

Time went passed and the things i did still haunted us. We usually dont have fights but if we had something then 95% the times my lies and wrong doings where brought out with names and i should write to them again. She did it out of anger i believe. We eased down and still had amazing times, we traveled, had new jobs etc. But there was always this kind of axe in our relationship and we felt the dension. Mostly from her as she still could not trust me fully. She truly believed and loved me so much. She tough i am so good and gentle with her and will be future father. I damaged her so deeply with my actions. Every time something went wrong she tough about these things again. Our sex got a bit worse also, as i said i think over and might go soft. If that happened i would be plasted with saying I want those girls in internet and watch porn. Next times was harder for me because i did not want to let her down as I adore her body and sexual lust. But still i think over about failing and it ruined things even more. It made things worse… Sometime i got over it and we had good times in bed. But sometimes they popped up again and in the end we had sex maybe 1 time a week. She told me sometimes that she cant be intimate with me as she sees all the pics and text in her mind that i had with others.

I understand now, how much i let her down and how little I did to be there for her. To get her trust back, i also got frustrated about her thinking that way etc. She even stalked my fb every day at work. I knew it but did not say anything, i wanted to show her trust and i am not falling to that bit again, but time went by and she still was not sure. I should have tried harder to show my love and talk about future for us i know my faults but little to late.

2-3 weeks ago she decided to end things with me. We decide that I will try to look for rent place and then we sell the apartment. I did not went full mental on her about how sorry i was. I was realized how much wrong i did, how little kid attitude i had. I cried a lot looking at her,i tried a bit to talk how i understand this mistake I have made. I received career promotion i was feeling more secure for making family but i was never open with her about it.
In these weeks she open account on tinder and already went out with some guy(29). I feel bad but i saw it in her Facebook… It was only one time thing, because i did not want mess things up more. But what I read was that she like the guy, he is fun, seems caring and they had date when i was still living there. Every evening i saw her smiling to computer and writing passionately with him in FB.

As I now moved out (3rd night alone), i am afraid how much more intimate she could get with him. Doing it in my/our apartment, what if she pays me and leaves the apartment for her… Screaming and panic toughs that i lost someone so good for me. Who never took me for granted and loved who i was.

I have taken my goal to make myself better, leave the porn and chating life behind me. To be a man, a grown up who takes responsibility of his actions. I understand that the first wake up call should have been the first cheat not the break up. But I was too comfortable, she took me back and i dint have these flows of emotions, i did not have this extra year with her and seeing the future.

It is so hard to thing what to do right now. Should i start no contact? But i cant as we are selling our apartment, maybe she thinks I am good and happy that we ended, what i am not. Should i try to explain my new views and even accept that i can live on my own and change myself.
Biggest fear is that this new guy from tinder is not some rebound but faith matched them in right time after me hurting her. So i dont have time to find myself, go to counsel, prove that i am changing to be a man she always tough i would be.

Sry for long post and hope you understand my situation. I know it is not feeling I dont want to be alone. I see how bad and wrong i have been. I have used her love against her and lost the trust we valued so much.
I am know i need to change myself, talk to someone and be honest about everything, be a man and take responsibility.
Thank you for listening.