I need ladies advice PLEASE 😔😭

Currently going threw a break up, let me back track a little, we actually broke up in January. But still remained in touch with eachother as we have 2 daughters together one who was only turning two in march, and one who was only 5 months, and I was 3 months pregnant with our 3rd. So we had to remain in contact, I missed him and wanted to make it work but he was disinterested. Saying he couldn't handle me breaking up with him all the time. (I had serious trust issues as he cheated on me and got his ex pregnant at the same time as me with our second daughter) so it was doomed from then on anyway, so we remained in contact and at times he was hot and cold, missing me one minute, not interested the next. I struggled threw. Then around April we slept together 3 times, only for me to find out he was back with her. So I stopped speaking to him, and completely cut him off, and for 3 months me nor my children seeen or heard from him, at this point I despised him, I had no interest in ever taking him back, and found my confidence again, I was doing amazing, and focused solely on my babies. And my home and myself. Even when he made contact again and started taking the kids. The love was still lost, I kept strong when he tried to play games, and wasn't interested in taking him back. UNTIL 5 weeks ago. When our son was born. And he came to the hospital declaring his love for me and how hes missed me, and has been so unhappy etc. I still kept strong (he thinks now because she dosent want him he can run to me) but then I found out he hasn't even really been with her in months. But anyways its almost like the pain and heartache of the breakup is only hitting me now, (we fell out again and he's blocked me, when hes getting our kids it's from day care and back, so we don't even have to see eachother, so I haven't seen or spoke to him now in 5 weeks. And the pain is unbearable, how do I cope with this. How do you ladies going threw breakups cope. I just want to be strong again. Now I miss him like batshit crazy, and in reality hes the biggest douche ever.