Just need some uplifting thoughts

My life has done a complete 360 these past few days. I don’t even know where to start anymore. To start my now ex fiancé and I had been together for 4 years. We have two kids together 3 year old and a almost 2 year old. We got into a argument this past weekend and he left the house for a night or so just to clear our heads. Well when he came back to talk we were just going to talk about the things we needed and goals we could set for our relationship in the future. So I thought. But once we sat down he told me he needed to get it off his chest and in order to change and be a better person he had to tell me and he told me he cheated on me and slept with another girl on a work trip back 3 fucking years ago when I was pregnant with our first child!!!! He has just now told me and since that I had our first and then we went on to have a second that’s now close to 2. 3 years of my life was wasted with lies and pain and me fighting for him everyday through any trial. Never cheating never giving up. He says he wanted to tell me now because he wants to change and this is the start to changing who he once was. That he wants to be the person that i need but I don’t know how I could ever go back. He’s completely totally ruined everything we ever had. All my trust all my security in him everything I ever had is gone! I’m also struggling now because now I will have to pay rent and full bills I am currently on track to go to nursing school right now and you can’t work many hours while in school here cause nursing school is like your full time job. How am I going to pay bills for my two kids and continue my career and work full time? I don’t know. Do I try to work things out since it was 3 years ago and never again since or do I move on and face the battle of school work and kids all alone. I’m so scared and so devastated. I just need input. Please no shaming me right now. I’m still really hurting.