Totally feeling trashed out

Hi, I am (36)(F) and already have 2 kids at their 20 and 18 and been single mkm for 14 years. 4 years ago I fell in love with my partner (M)(42) and have given a baby now 10months. He have 4 kids also. So we are just a very big family. Two months ago, I find it odd, one day, I woke up I feel he is cheating on me and to my guts I discovered it a few days back. He admitted to his sin, to my family and his family. I am completely shattered with this since I am battling with my post partum blues and here goes another one. He ask for my forgiveness and a week away from us to find himself leaving me forcing me to stand and be okay to fend for our baby. Now, I tried to download the app in which I caught him by his sin, to found out he still has it in his phone. I confronted him about that. He said he will fix it and not even messaging the girl. I just don't know why he still have it or shall I believe and trust to the space he needed. I just don't know where and how to pick up myself. I feel garbage. I want to trash myself voluntarily. I tried sui ide so many times but even hell wouldn't keep me in. Sometimes I wanted to say can I just be selfish for myself not thinking about my kids. It's really painful tbat I want to dissolve now.