I cannot forgive myself/ I cheated

PS: lengthy read about my relationships

We were in a long-term relationship. I had never put effort into this relationship as much as my partner. It was always a contrast; I was always prioritizing other things and not giving a damn about the relationship. Fast forward, my partner thought it was good to be in another country for the relationship and also for the career and moved to another country; it became long-distance. Then I moved to my partner after so much. Most of the effort was also done by my partner. Everything was going on quickly, I couldn't adapt, and I felt very lonely and alone. Even though it was the same country, the distance was again like far between me and my partner.

I somehow got some friends and gelled with them. In the meantime, I could not put effort in again because I got new friends and was busy with my own stuff. I got close to a friend, and that friend showed interest, and I moved and cheated. It was my mistake all along. After that, I confessed to my partner, and we separated and got back together after some time. But I could not forgive myself, and my partner was in trauma with so many other problems because of my mistakes.

It went okay for some time, but I felt worse every time. I couldn't come out of the guilt, and I felt like dying. I told her the same and separated with my partner again, putting my partner through such a bad and hard time. I really feel bad for my partner. How bad of a person I am.

While I was in this phase, I had friends, and I met a friend who understood everything I did and accepted me as I am. I felt like it was a relieving feeling. Then we were close, and one day we became physically close as well. At that time, it had been months with my ex since I told her I was guilty and stuff and that I can't be with her. She cried like anything to be back, but at that point, it was suffocating me. Every time we do anything or talk, I get reminded of my mistakes. This felt like an escape, but it was just me escaping my guilt. Then we went on to a relationship for some time. Then we both realized we are not compatible at anything and got separated, but I'm still stuck with my first partner.

How cruel of a human being I am to hurt all the people who were in relationships with me. I literally can't sleep day or night, and it causes immense pain which I can't describe, and it feels like I don't deserve to live and feeling like going away from this earth somehow. I don't have many friends, or they don't know much to share. I feel very alone, lonely, and depressed. It affects my professional and personal life. I am getting panic attacks and blood pressure. I don't know, I just post here so it reaches the right person or someone who could help me. I can't forgive myself thinking about the pain I caused to my partner because of my stupid, immature, and naive being. Idk how to proceed with my life, please help