Toxic relationships

How do I feel ok again after the ending of a 3 year toxic relationship? I know mentally this is what’s right, I know I deserve better and I know I don’t want my kids to see this type of relationship. But it still feels so awful & it’s still so hard to let go of him and not do what I usually do and send him a million messages and just end up geting back with him. I miss him already, even though most of the time I was with him was hearing how much he didn’t care about me how fat and ugly I was and just such a negative time it’s like I always feel better when I’m with him even through the negatives. It’s sick I wanna say that I respect myself more but I don’t I guess. I’d be with him forever even though it’s costed me my self esteem and my sanity , it’s selfish of me but it’s like a drug. I know it’s so bad but I only feel better when I get back with him. How do I get through this for my daughter and my son on the way. I have a month until he’s here & I can’t picture doing this without my man. It’s like even though he’s the meanest person to me, in some sick way I’ve considered him my best friend. I’ve realized that my relationship with him is the 80/20 rule, but my 80% is negative and the 20% that’s positive I thrive off of that. I live for those times where he’s all over me and actually wants to be around me and spend time with me and when we’re laughing. I feel like a piece of me is gone even though I’ve been mentally preparing for this for so long. I knew he wanted other girls, he didn’t apologize when he gets caught talking to them. I knew he didn’t give a shit about me, he told me a billion times, but why’s it hurt so much to know it’s over and imnot gonna deal w his attitude anymore. If anyone has actually been in a toxic relationship and knows where I’m coming from, and has any similar situations and understands that it’s not easy to just up and leave someone who treats u poorly please leave ur experiences, ur opinions anything. I think this is more of a way to vent& say what I have to say bc he’s the last person to listen and i just needed to get it all out.