Moving forward

My kids father and I got back together about six months ago. Prior to this he broke up with me and immediately got with someone else. That relationship didn't work out and he begged me to give our relationship another try. Everything was perfect at first but as usual things got bad. He ended up getting evicted from his apartment and relied on me to provide him with somewhere else to live. He suggested that we get an apartment and live together with the kids. Problem was he refused to help me get the apartment. He put so much pressure on me to get the apartment and constantly yelled and belittled me got him still being homeless. He even went to his family and friends and cried to them telling them I was the reason he was still in his current situation. He told me that as his girlfriend it was my responsibility to take care of him. Yet, he refused to help me with the kids. He has a job and is always struggling financially even though he has no bills. I then found out that it's because he's always spending money on prostitutes and drinking at bars and buying himself clothes. When I would confront him he would tell me I was crazy and insecure and that unless I saw him having sex with someone I had no right to be upset. Things got worst and I eventually saw him contacting transvestites. I tried so many times to leave and every single time he would stalk and threaten me. He would call my phone over and over again nonstop while leaving rude voicemails. Telling me I was a horrible mom and he would take my kids from me since I didn't wanna be with him. So I would always go back. It became routine for him to sleep with prostitutes and yell at me when I found out and threaten me if I tried leaving. I felt trapped. Shortly after I find out I'm pregnant and I got to the docters for a Pap smear and std test. My test returned positive for an std. Thank god is was a curable one. This time I was determined to leave, but I felt guilty because he tried to kill himself. A few weeks ago he found a new girl at a bar and everything changed. He broke up with me and refused to speak to me. He only started speaking to me again since the relationship wasn't working out. I've asked him repeatedly to only text me and not to call. I'm trying really hard to move on this time. He refuses to respect my boundaries and tells me he can do whatever he wants because I have his kids. When I do answer his phone calls he sends mixed signals. Somedays he crying and complaining about us not being together and blames me for him having to breakup with me. Then tells me our kids will suffer because they don't have a family. Then other days he's completely cold and distant and tells me he dislikes me and I make his stomach turn. That he would love to take his kids and have me disappear. That if I we're dead he would be a lot happier. I tell him if that's the case just stop contacting me and pretend like I'm dead. Yet he still calls. He's confusing me and stressing me out. He says he's completely over me and doesn't care about me yet he refuses to leave me alone. I just wanna move on. Any advice??