Loneliness, emptiness, lack of motivation, suicidal thoughts

Hello!

I was in a relationship with a man for about 3 years. Toward the end of our time together, he began to treat me poorly, often abusing me mentally and choosing not respect my feelings. Things ended and I chased after him for about a year and a half. Throughout that time, he took advantage of being single and slept with many girls. A couple of months later I began seeing another man. Eventually, I became his girlfriend. My ex and I had always remained in contact, even after the break-up and when he found out I was dating someone new, he decided to tell me he wanted to fix things with me. Obviously, I told him that was not a possibility, but considering I regarded him as a friend, I remained in contact with him nonetheless. Nothing ever happened between us and when he would ask me to see him, I always refused. The new guy in my life found out we had spoken a couple of times, and he asked what my ex's intentions were. I wanted to be honest so I told him that he was trying to get back with me. He was very hurt that I still spoke to him and asked me to stop doing so. I did for a while and 2 months later, he discovered a one-hour phone call I had had with my ex. He was in shock since he had asked me not to speak to him and I had broken his trust. He gave me one more chance to never pick up his calls again or he said he would leave me. A couple of months after that, I told him that my ex and I spoke but that I picked up only to tell him to stop calling me. My boyfriend was furious, and he could not understand why I would disrespect him and not take into consideration his feelings once again. He broke up with me shortly after, and said he tried to forget about the call but that he simply couldn't trust me anymore. I am devastated at the moment because I feel like I lost someone very special to me and I know I was given many chances to prove myself but that I still let him down. I know we will never get back together because he is very stubborn but I don't know how to manage the feelings of guilt and regret and I live with them daily. Any advice on how to move on with my life without falling into a deep depression, because I feel that is where I am headed...