How do I do it

I'm 27 and my ex is 28. We were together 4 years , lived together the entire time, had many pregnancy losses and even a still born son. Idk where things went wrong but no matter what we went through I knew he was my person I wanted him through anything. In the beginning I dealt with him watching porn when we discussed we wasn't going to do that, had issues with him and his ex and him searching random girls on social media. Got past that , and started fighting all the time . The love was strong but we had many issues. He wasn't very attentive, wouldn't hold my hand in public, would walk ahead of me , never showed affection etc. We fought a lot about him always being on his phone and not putting in effort to fix our problems. It got to the point I was crying and begging him to just pay attention to me.to. he started accusing me of cheating and doing drugs but he was the one failing drug tests and more than likely cheating. I really wanted the simple free things that come with a partnership nd he just couldn't give them and always blamed it on his parents marriage. Towards the end of our relationship I knew it was ending but didn't want that at all. This man literally lied told me we was going to elope , helped me plan and watched me order a dress that was sent to our home, we continued to try for a child, and he was telling me he loves me still at this point. Welli truly wanted this to work and was willing to do anything he just wouldn't even try and we fought one day ,I left for a brief min to calm down and come back to our home to him packing everything in the house up and moving out. I was so broken. It's been a month and I'm so sad still. Idk why but I just wanted this to work so bad. There's been no contact and seems he's moving on that literally breaks me down. So many unanswered questions I have, a broken heart etc. I miss him bad, I've tried hanging with new people and moving on myself but this wasn't what I wanted so I'm having a rough time not thinking about him. I just want him back and he doesn't deserve that. He keeps lying to people saying it's an amicable split but I definitely didn't want this. He never even told me he was done he tried to move out before I got home and got caught like a coward. How do I heal and start to move on from this. When you share a life with someone it's tricky when you no longer have that