My husband left me and our 3 children while I'm 6 months pregnant with twins

My husband and I have been married for 3 years we have 3 children one of which is from a previous relationship, and twins on the way. Recently my husband left me and my kids, once he left he changed his number and wanted no communication with me or his kids at all. I did not know where he was or anything about him. I reached out to his mom she only told me to just let him be and to just move on. Which is where I went to talk to a lawyer to file a separation. My husband would call me every few days private because I would tell his mom to have him call me at this time I was also considering putting my twins up for adoption, don't get me wrong I love my children but when my husband left I did not have the income to take care of all 5 by myself. I thought this would be the next best thing for them. When he would call I would ask him to meet me to sign the adoption and separation papers he would tell me a time and place and I would go and wait hours, he would not show up not call nothing. This happened about three or 4 times. I was not able to work because my husband would watch our kids while I worked vice versa, so I was really tight on money I did not have money to feed me or my children no buy anything they needed, when he finally called again I asked him for money to keep up for a while he agreed and once again told me to meet him and he never showed. After weeks of this happening I was forced to move in with my parents and find a sitter to watch my children. I finally decided to go to his job to talk to him and see why he was doing this to our family once I got there he was furious he told me to never come to his job with his kids ever again. I was very emotional because as I was looking at him and the anger in his face like he did not miss his family he also had a hickey on his neck I asked him about and he laughed in my face saying it was nothing. Which that made me only cry more, my children missed there father so much I had to pull them out for us to leave because he said we had to leave and he did not want to talk to me right now. So I left and waited in the parking lot. I couldn't bring myself to just leave without knowing why, why is he doing this to me. I had to beg his mom to tell him to come out to talk to me he finally did and he yelled and sceamed at me telling me to stop crying that he needed a break. I couldn't understand why my husband of three years was acting like this. I begged him to just come home with me to talk then he could leave. I just wanted to talk he would not. So I asked him to sign the papers because this is what he seemed like he wanted he still would not. Then he left.. I tried to move on after this day but I could not I would cry myself to sleep asking what I did wrong, I would think about taking my life to stop all the pain I was feeling. I could barely bring myself to go to work go to doctors appointments anything. I really had no one to talk to. The only person I've had for 4 years was my husband he was my everything. Weeks went by he would call some days to just tell at me for crying all the time or for calling his job looking for him. I just wanted to make sure he was ok. He missed both of our daughters birthdays. A few more days passed and he began calling more talking to me more saying he missed me and the kids. You don't understand how happy I was so I met with him finally and he saw the kids. He told me after he worked he would get his things and come back home. I was so happy. So I waited for him all night and he never showed or called two days passed and I finish heard from him again he said he need to handle some things that's why he didn't come he asked me if I wanted him to come home still and I said yes. Because I did. I love my husband so much. So he told me to pick him up after I got off work and I did. Days passed and everything was completely different the way he acted towards me everything we finally had sex and it was like a person I didn't even know. I had to force him to touch me. Force him to lay next to me. All I could do was cry. It's like I lost the only person I've know. I asked him while he was gone did he cheat on me he made promise after promise that he did not . The day that I picked him up he gave me his new number. That next day he changed it again and told me to many people had his number that was why. I went with it. A few days ago. I checked his social media account and there was messages for people I didn't know. They were asking him why he hurt this girl or why he did he bogus just to leave her. When I continued reading them that's when the truth came out he was having a affair with someone else and left her to come back with me. At the point I felt like my life was over everything I knew was a lie. My marriage, the person I love so much. Everything. I bought up what I had found out to him and all he could say was I don't want to be with him that I don't love him. I don't know what else to do I don't want to leave him but I can't let him keep doing this to me. This has not been the first time he has left me but this time was the most extreme. Someone please give me any type of advice.

Thank you.