Hurt and need advice please. Sry it’s long 😢

Ok so here is my problem..... last spring my friend ( at the time) introduced me to her friend to see if we would hit it off...well we did and then a few short months went by and he left me for his ex who came back from rehab. I then had my own problems and it landed me in a bad place not only with myself but my family too. So I was doing so good and started working again this winter and was happy and then he comes back into my life and wants another chance...so I gave it to him mind you I had some trust issues with the situation from before and how things where now. He was living at another girls house cuz he had no place to live and can’t work. I had no idea that when we got back together he was using drugs till a few weeks of dating. He said it wasn’t anything big he could stop and things just got worse and worse and I ended up losing my job because I was afraid that he would od yet again. He ended up getting sick and in the hospital for three weeks and I didn’t leave his side I stayed there everyday and night for three weeks mind you 6-1/2 months pregnant. Then he went to another place for three more weeks of iv treatment and I would go see him everyday. Well before I had my daughter we were getting into fights because he would sit there and talk to his ex either in text or on the phone when he thought I wasn’t listening or around to hear mind you this is he same ex he left me for. So when it came time for me to deliver I had text him and said I’m in labor and he never answered me he had gone that night before with his ex and didn’t bother to man up and tell me he was back with her. I was so hurt that I wanted to just give up because this is a man that I gave my everything to and gave shit up in my life for and I thought he loved me as much as I loved him. But now that he is gone I’m still depressed and cry myself to sleep while snuggling my little girl to ty and feel better. My ex had reached out to me a few months before I had my daughter and he wants to give things another go because he said he was wrong and should. Have never left me in the summer and that I wouldn’t be in this situation with my other ex if he had just stayed. So do you think it’s ok to date my other ex again after being done so wrongly by my other ex? Should I date him because I’m lonely right now and hurting but do care about him? I mean my daughter is only 8 days old and my emotions are all over the place I just don’t know what to do?